Version: tip
OS: Linux

What steps will reproduce the problem?
(1) Build mojo_system_unittests in the official mode:
$ gn gen out/gn-off '--args=is_chrome_branded=true is_official_build=true is_debug=false' --check
$ ninja -C out/gn-off mojo_system_unittests

(2) Run mojo_system_unittests:
$ ./out/gn-off/mojo_system_unittests
...
Retrying 2 tests (retry #1)
[ RUN      ] OptionsValidationTest.InvalidDeath
../../mojo/edk/system/options_validation_unittest.cc:103: Failure
Death test: { UserOptionsReader<TestOptions> reader((nullptr)); }
    Result: died but not with expected error.
  Expected: Check failed
Actual msg:
[  DEATH   ] [11813:11813:0517/101212:589892447147:WARNING:test_suite.cc(195)] Test launcher output path /tmp/.com.google.Chrome.BYGarC/test_results.xml exists. Not adding test launcher result printer.
[  DEATH   ] Received signal 4 ILL_ILLOPN 000000497f67
[  DEATH   ] #0 0x00000059dcb7 (/usr/local/google/home/krasin/chr22/src/out/gn-off/mojo_system_unittests+0x59dcb6)
[  DEATH   ]   r8: 0000000000000000  r9: 00007ffc420f1ec0 r10: 0000000000000001 r11: 00007f75ea5dd870
[  DEATH   ]  r12: 00002f6955326e00 r13: 00002f6955326e00 r14: 00002f6955368940 r15: 00002f6955323500
[  DEATH   ]   di: 00002f6955368940  si: 0000000000000004  bp: 0000000000000002  bx: 00002f6955368940
[  DEATH   ]   dx: 0000000000000000  ax: 0000000000000001  cx: 00002f6955329c20  sp: 00007ffc420f1e40
[  DEATH   ]   ip: 0000000000497f67 efl: 0000000000010202 cgf: 0000000000000033 erf: 0000000000000000
[  DEATH   ]  trp: 0000000000000006 msk: 0000000000000000 cr2: 0000000000000000
[  DEATH   ] [end of stack trace]
[  DEATH   ] 
../../mojo/edk/system/options_validation_unittest.cc:111: Failure
Death test: { UserOptionsReader<TestOptions> reader( reinterpret_cast<const TestOptions*>(1)); }
    Result: died but not with expected error.
  Expected: Check failed
Actual msg:
[  DEATH   ] [11815:11815:0517/101212:589892454348:WARNING:test_suite.cc(195)] Test launcher output path /tmp/.com.google.Chrome.BYGarC/test_results.xml exists. Not adding test launcher result printer.
[  DEATH   ] Received signal 4 ILL_ILLOPN 000000497f67
[  DEATH   ] #0 0x00000059dcb7 (/usr/local/google/home/krasin/chr22/src/out/gn-off/mojo_system_unittests+0x59dcb6)
[  DEATH   ]   r8: 0000000000000000  r9: 00007ffe547bfd80 r10: 0000000000000001 r11: 00007f7e17660870
[  DEATH   ]  r12: 00000a17593e6e00 r13: 00000a17593e6e00 r14: 00000a1759428940 r15: 00000a17593e3500
[  DEATH   ]   di: 00000a1759428940  si: 0000000000000004  bp: 0000000000000004  bx: 00000a1759428940
[  DEATH   ]   dx: 0000000000000000  ax: 0000000000000001  cx: 00000a17593e9c20  sp: 00007ffe547bfd00
[  DEATH   ]   ip: 0000000000497f67 efl: 0000000000010202 cgf: 0000000000000033 erf: 0000000000000000
[  DEATH   ]  trp: 0000000000000006 msk: 0000000000000000 cr2: 0000000000000000
[  DEATH   ] [end of stack trace]
[  DEATH   ] 
../../mojo/edk/system/options_validation_unittest.cc:125: Failure
Death test: { uint32_t buffer[100] = {}; TestOptions* options = (reinterpret_cast<uintptr_t>(buffer) % 8 == 0) ? reinterpret_cast<TestOptions*>(&buffer[1]) : reinterpret_cast<TestOptions*>(&buffer[0]); options-
>struct_size = static_cast<uint32_t>(sizeof(TestOptions)); UserOptionsReader<TestOptions> reader(options); }
    Result: died but not with expected error.
  Expected: Check failed
Actual msg:
[  DEATH   ] [11817:11817:0517/101212:589892461283:WARNING:test_suite.cc(195)] Test launcher output path /tmp/.com.google.Chrome.BYGarC/test_results.xml exists. Not adding test launcher result printer.
[  DEATH   ] Received signal 4 ILL_ILLOPN 000000497f67
[  DEATH   ] #0 0x00000059dcb7 (/usr/local/google/home/krasin/chr22/src/out/gn-off/mojo_system_unittests+0x59dcb6)
[  DEATH   ]   r8: 0000000000000000  r9: 00007ffd8d4ab540 r10: 0000000000000001 r11: 00007fed85307870
[  DEATH   ]  r12: 00003dc387f53e00 r13: 00003dc387f53e00 r14: 00003dc387f95940 r15: 00003dc387f50500
[  DEATH   ]   di: 00007ffd8d4ab5c0  si: 0000000000000000  bp: 0000000000000000  bx: 00003dc387f95940
[  DEATH   ]   dx: 00007ffd8d4ab740  ax: 00007ffd8d4ab5c0  cx: 00007ffd8d4ab740  sp: 00007ffd8d4ab540
[  DEATH   ]   ip: 0000000000497f67 efl: 0000000000010246 cgf: 0000000000000033 erf: 0000000000000000
[  DEATH   ]  trp: 0000000000000006 msk: 0000000000000000 cr2: 0000000000000000
[  DEATH   ] [end of stack trace]
[  DEATH   ] 
[  FAILED  ] OptionsValidationTest.InvalidDeath (23 ms)
[161/162] OptionsValidationTest.InvalidDeath (23 ms)
[ RUN      ] CoreTest.InvalidArgumentsDeath
../../mojo/edk/system/core_unittest.cc:457: Failure
Death test: core()->WaitMany(nullptr, &signals, 1, MOJO_DEADLINE_INDEFINITE, nullptr, nullptr)
    Result: died but not with expected error.
  Expected: Check failed
Actual msg:
[  DEATH   ] [11821:11821:0517/101212:589892486856:WARNING:test_suite.cc(195)] Test launcher output path /tmp/.com.google.Chrome.nbTM2p/test_results.xml exists. Not adding test launcher result printer.
[  DEATH   ] Received signal 4 ILL_ILLOPN 00000050018e
[  DEATH   ] #0 0x00000059dcb7 (/usr/local/google/home/krasin/chr22/src/out/gn-off/mojo_system_unittests+0x59dcb6)
[  DEATH   ]   r8: ffffffffffffffff  r9: 00007ffede22bc74 r10: 0000000000000001 r11: 00007f97ea0d0870
[  DEATH   ]  r12: 00007ffede22bddc r13: 0000000000000000 r14: 00000a4ef44bcb00 r15: ffffffffffffffff
[  DEATH   ]   di: 00000a4ef44bcb00  si: 0000000000000000  bp: 0000000000000001  bx: 0000000000000001
[  DEATH   ]   dx: 00007ffede22bddc  ax: a4e15e69ca4a9400  cx: 0000000000000001  sp: 00007ffede22bb30
[  DEATH   ]   ip: 000000000050018e efl: 0000000000010246 cgf: 0000000000000033 erf: 0000000000000000
[  DEATH   ]  trp: 0000000000000006 msk: 0000000000000000 cr2: 0000000000000000
[  DEATH   ] [end of stack trace]
[  DEATH   ] 
[  FAILED  ] CoreTest.InvalidArgumentsDeath (7 ms)
[162/162] CoreTest.InvalidArgumentsDeath (7 ms)
2 tests failed:
    CoreTest.InvalidArgumentsDeath (../../mojo/edk/system/core_unittest.cc:447)
    OptionsValidationTest.InvalidDeath (../../mojo/edk/system/options_validation_unittest.cc:97)

The tests only fail in the official mode. That was uncovered by the new 'LTO Linux' buildbot, but it turned out that the failure has nothing to do with LTO, and reproduces in the regular build as well.

Please, take a look.