Crashing tests seem to be outputting XML test-result output on stderr/stdout.

e.g. Running the currently-failing PlatformWrapperTest.WrapPlatformHandle, after the test failure & crash, we also get logged:

[00004.879] 03439.03468> [3:-640369872:0810/192519.043837:4859326:FATAL:test_suite.cc(241)] Check failed: printer_->Initialize(output_path).
----- start symbolized stack
#00: StackTrace at /usr/local/google/home/wez/Projects/git-cr-fuchsia/src/out/gnDebug/../../base/debug/stack_trace_fuchsia.cc:169
#01: StackTrace at /usr/local/google/home/wez/Projects/git-cr-fuchsia/src/out/gnDebug/../../base/debug/stack_trace.cc:199
#02: ~LogMessage at /usr/local/google/home/wez/Projects/git-cr-fuchsia/src/out/gnDebug/../../base/logging.cc:?
#03: base::TestSuite::AddTestLauncherResultPrinter() at /usr/local/google/home/wez/Projects/git-cr-fuchsia/src/out/gnDebug/../../base/test/test_suite.cc:243
#04: base::TestSuite::Initialize() at /usr/local/google/home/wez/Projects/git-cr-fuchsia/src/out/gnDebug/../../base/test/test_suite.cc:402
#05: base::TestSuite::Run() at /usr/local/google/home/wez/Projects/git-cr-fuchsia/src/out/gnDebug/../../base/test/test_suite.cc:260
#06: int base::internal::FunctorTraits<int (base::TestSuite::*)(), void>::Invoke<base::TestSuite*>(int (base::TestSuite::*)(), base::TestSuite*&&) at /usr/local/google/home/wez/Projects/git-cr-fuchsia/src/out/gnDebug/../../base/bind_internal.h:196
#07: int base::internal::InvokeHelper<false, int>::MakeItSo<int (base::TestSuite::* const&)(), base::TestSuite*>(int (base::TestSuite::* const&)(), base::TestSuite*&&) at /usr/local/google/home/wez/Projects/git-cr-fuchsia/src/out/gnDebug/../../base/bind_internal.h:265
#08: int base::internal::Invoker<base::internal::BindState<int (base::TestSuite::*)(), base::internal::UnretainedWrapper<base::TestSuite> >, int ()>::RunImpl<int (base::TestSuite::* const&)(), std::__1::tuple<base::internal::UnretainedWrapper<base::TestSuite> > const&, 0ul>(int (base::TestSuite::* const&)(), std::__1::tuple<base::internal::UnretainedWrapper<base::TestSuite> > const&, base::IndexSequence<0ul>) at /usr/local/google/home/wez/Projects/git-cr-fuchsia/src/out/gnDebug/../../base/bind_internal.h:340
#09: base::internal::Invoker<base::internal::BindState<int (base::TestSuite::*)(), base::internal::UnretainedWrapper<base::TestSuite> >, int ()>::Run(base::internal::BindStateBase*) at /usr/local/google/home/wez/Projects/git-cr-fuchsia/src/out/gnDebug/../../base/bind_internal.h:319
#10: base::Callback<int (), (base::internal::CopyMode)1, (base::internal::RepeatMode)1>::Run() const & at /usr/local/google/home/wez/Projects/git-cr-fuchsia/src/out/gnDebug/../../base/callback.h:80
#11: base::(anonymous namespace)::LaunchUnitTestsInternal(base::Callback<int (), (base::internal::CopyMode)1, (base::internal::RepeatMode)1> const&, unsigned long, int, bool, base::Callback<void (), (base::internal::CopyMode)1, (base::internal::RepeatMode)1> const&) at /usr/local/google/home/wez/Projects/git-cr-fuchsia/src/out/gnDebug/../../base/test/launcher/unit_test_launcher.cc:216
#12: base::LaunchUnitTests(int, char**, base::Callback<int (), (base::internal::CopyMode)1, (base::internal::RepeatMode)1> const&) at /usr/local/google/home/wez/Projects/git-cr-fuchsia/src/out/gnDebug/../../base/test/launcher/unit_test_launcher.cc:475
#13: main at /usr/local/google/home/wez/Projects/git-cr-fuchsia/src/out/gnDebug/../../mojo/edk/test/run_all_unittests.cc:46
#14: mojo_system_unittests+0x1c22e
----- end symbolized stack
[00004.879] 03439.03468>
[00004.887] 03439.03468>       <x-test-result-part type="fatal_failure" file="../../base/test/test_suite.cc" line="241">
[00004.888] 03439.03468>         <summary>Q2hlY2sgZmFpbGVkOiBwcmludGVyXy0+SW5pdGlhbGl6ZShvdXRwdXRfcGF0aCkuIA==</summary>
[00004.888] 03439.03468>         <message>Q2hlY2sgZmFpbGVkOiBwcmludGVyXy0+SW5pdGlhbGl6ZShvdXRwdXRfcGF0aCkuIAojMDAgMHgyZTFjYjMwNTM0YTAgYXBwOi9zeXN0ZW0vbW9qb19zeXN0ZW1fdW5pdHRlc3QrMHg4YWE0YTAKIzAxIDB4MmUxY2IyZDZkODNjIGFwcDovc3lzdGVtL21vam9fc3lzdGVtX3V
[00004.888] 03439.03468> uaXR0ZXN0KzB4NWM0ODNjCiMwMiAweDJlMWNiMmQ2NWVmYSBhcHA6L3N5c3RlbS9tb2pvX3N5c3RlbV91bml0dGVzdCsweDViY2VmYQojMDMgMHgyZTFjYjMwNjM2M2UgYXBwOi9zeXN0ZW0vbW9qb19zeXN0ZW1fdW5pdHRlc3QrMHg4YmE2M2UKIzA0IDB4MmUxY2IzMDY0MjJhIGFwcDovc3lzdGV
[00004.888] 03439.03468> tL21vam9fc3lzdGVtX3VuaXR0ZXN0KzB4OGJiMjJhCiMwNSAweDJlMWNiMzA2MmFkMCBhcHA6L3N5c3RlbS9tb2pvX3N5c3RlbV91bml0dGVzdCsweDhiOWFkMAojMDYgMHgyZTFjYjJhZjliMWQgYXBwOi9zeXN0ZW0vbW9qb19zeXN0ZW1fdW5pdHRlc3QrMHgzNTBiMWQKIzA3IDB4MmUxY2IyYWY
[00004.888] 03439.03468> 5YTY0IGFwcDovc3lzdGVtL21vam9fc3lzdGVtX3VuaXR0ZXN0KzB4MzUwYTY0CiMwOCAweDJlMWNiMmFmOWExNSBhcHA6L3N5c3RlbS9tb2pvX3N5c3RlbV91bml0dGVzdCsweDM1MGExNQojMDkgMHgyZTFjYjJhZjk5MmMgYXBwOi9zeXN0ZW0vbW9qb19zeXN0ZW1fdW5pdHRlc3QrMHgzNTA5MmM
[00004.888] 03439.03468> KIzEwIDB4MmUxY2IzMDdjNzlkIGFwcDovc3lzdGVtL21vam9fc3lzdGVtX3VuaXR0ZXN0KzB4OGQzNzlkCiMxMSAweDJlMWNiMzA3NWIwNyBhcHA6L3N5c3RlbS9tb2pvX3N5c3RlbV91bml0dGVzdCsweDhjY2IwNwojMTIgMHgyZTFjYjMwNzU5NzUgYXBwOi9zeXN0ZW0vbW9qb19zeXN0ZW1fdW5
[00004.888] 03439.03468> pdHRlc3QrMHg4Y2M5NzUKIzEzIDB4MmUxY2IyYWY5NTk3IGFwcDovc3lzdGVtL21vam9fc3lzdGVtX3VuaXR0ZXN0KzB4MzUwNTk3CiMxNCAweDZmNzEwMjQ5NDIyZSBsaWJjLnNvKzB4MWMyMmUKIzE1IGVuZAoK</message>
[00004.888] 03439.03468>       </x-test-result-part>