See e.g. https://build.chromium.org/p/chromium.fyi/builders/ClangToTWin%28dbg%29%20tester/builds/2318

These tests fail:

LazyBackgroundPageApiTest.NaClInBackgroundPage
LazyBackgroundPageApiTest.NaClInView
MediaGalleriesPlatformAppPpapiTest.SendFilesystem
NaClBrowserTestGLibc.ExitStatus0
NaClBrowserTestGLibc.ExitStatus254
NaClBrowserTestGLibc.ExitStatusNeg2
NaClBrowserTestGLibc.PPAPICore
NaClBrowserTestGLibc.PPAPIPPBInstance
NaClBrowserTestGLibc.PPAPIPPPInstance
NaClBrowserTestGLibc.ProgressEvents
NaClBrowserTestGLibc.SimpleLoad
NaClBrowserTestGLibc.SuccessfulLoadUMA
NaClBrowserTestGLibcVcacheExtension.ValidationCacheOfMainNexe
NaClBrowserTestNewlib.BadNative
NaClBrowserTestNewlib.ExitStatus0
NaClBrowserTestNewlib.ExitStatus254
NaClBrowserTestNewlib.ExitStatusNeg2
NaClBrowserTestNewlib.IrtManifestFile
NaClBrowserTestNewlib.PPAPICore
NaClBrowserTestNewlib.PPAPIPPBInstance
NaClBrowserTestNewlib.PPAPIPPPInstance
NaClBrowserTestNewlib.ProgressEvents
NaClBrowserTestNewlib.SimpleLoad
NaClBrowserTestNewlib.SuccessfulLoadUMA
NaClBrowserTestNewlibVcacheExtension.ValidationCacheOfMainNexe
NaClGdbTest.Empty
NewlibPackagedAppTest.MulticastPermissions
NewlibPackagedAppTest.NoSocketPermissions
NewlibPackagedAppTest.SocketPermissions
NewlibPackagedAppTest.SuccessfulLoad
PPAPINaClGLibcTest.Audio
PPAPINaClGLibcTest.AudioConfig
PPAPINaClGLibcTest.AudioThreadCreator
PPAPINaClGLibcTest.UDPSocket_Broadcast
PPAPINaClGLibcTest.UDPSocket_Multicast
PPAPINaClGLibcTest.UDPSocket_ParallelSend
PPAPINaClGLibcTest.UDPSocket_ReadWrite
PPAPINaClGLibcTest.UDPSocket_SetOption
PPAPINaClGLibcTest.UDPSocket_SetOption_1_0
PPAPINaClGLibcTest.UDPSocket_SetOption_1_1
PPAPINaClNewlibTest.Audio
PPAPINaClNewlibTest.AudioConfig
PPAPINaClNewlibTest.AudioEncoder
PPAPINaClNewlibTest.AudioThreadCreator
PPAPINaClNewlibTest.Console
PPAPINaClNewlibTest.Core
PPAPINaClNewlibTest.FileRef1
PPAPINaClNewlibTest.FileRef2
PPAPINaClNewlibTest.Graphics2D_BindNull


They all fail with nacl load errors; here's an example:

[ RUN      ] NaClBrowserTestGLibc.PPAPIPPBInstance
[6104:2248:0510/034050:INFO:nacl_browsertest_util.cc(130)] |||| [STARTUP]
[6104:2248:0510/034050:INFO:CONSOLE(0)] "NativeClient: manifest: no version of program given for current arch and no portable version found.", source: http://127.0.0.1:49877/ppapi_ppb_instance.html (0)
[6104:2248:0510/034050:INFO:nacl_browsertest_util.cc(130)] ||||
[CLIENT_ERROR]  / test_nexe did not load. Status: DONE / 'NaCl module load failed: manifest: no version of program given for current arch and no portable version found.'
[6104:2248:0510/034050:INFO:nacl_browsertest_util.cc(130)] ||||
[6104:2248:0510/034050:INFO:nacl_browsertest_util.cc(130)] |||| A nexe load error occured, aborting testing.
[6104:2248:0510/034050:INFO:nacl_browsertest_util.cc(130)] ||||
[6104:2248:0510/034050:INFO:nacl_browsertest_util.cc(130)] |||| [SHUTDOWN] 0 passed, 0 failed, 1 errors
[6104:4732:0510/034050:WARNING:embedded_test_server.cc(190)] Request not handled. Returning 404: /favicon.ico
../../chrome/test/nacl/nacl_browsertest_util.cc(254): error: Value of: handler.test_passed()
  Actual: false
Expected: true
Test failed.
[  FAILED  ] NaClBrowserTestGLibc.PPAPIPPBInstance, where TypeParam =  and GetParam() =  (3082 ms)



I guess the test next doesn't get built for 32-bit, or the 32-bit filename is wrong, or something like that.