runtime: Test failures in hashing on Browser

https://helixre8s23ayyeko0k025g8.blob.core.windows.net/dotnet-runtime-refs-pull-69668-merge-9dd411182c95433daa/WasmTestOnBrowser-System.Security.Cryptography.Tests/1/console.fdc2faf5.log?helixlogtype=result

[08:20:42] info: Starting:    System.Security.Cryptography.Tests.dll
[08:20:46] fail: [FAIL] System.Security.Cryptography.Tests.Sha1ManagedTests.Sha1_Rfc3174_3_Async
[08:20:46] info: Showing first 10 differences
[08:20:46] info:   Position 0: Expected: 52, Actual: 217
[08:20:46] info:   Position 1: Expected: 170, Actual: 73
[08:20:46] info:   Position 2: Expected: 151, Actual: 231
[08:20:46] info:   Position 3: Expected: 60, Actual: 108
[08:20:46] info:   Position 4: Expected: 212, Actual: 115
[08:20:46] info:   Position 5: Expected: 196, Actual: 7
[08:20:46] info:   Position 6: Expected: 218, Actual: 236
[08:20:46] info:   Position 7: Expected: 164, Actual: 195
[08:20:46] info:   Position 8: Expected: 246, Actual: 62
[08:20:46] info:   Position 9: Expected: 30, Actual: 42
[08:20:46] info: Total number of differences: 20 out of 20
[08:20:46] info:    at System.AssertExtensions.SequenceEqual[Byte](ReadOnlySpan`1 expected, ReadOnlySpan`1 actual)
[08:20:46] info:    at System.AssertExtensions.SequenceEqual[Byte](Span`1 expected, Span`1 actual)
[08:20:46] info:    at System.Security.Cryptography.Tests.HashAlgorithmTestDriver.VerifyOneShotStreamAsync(Stream input, String output)
[08:20:46] info:    at System.Security.Cryptography.Tests.HashAlgorithmTestDriver.VerifyRepeatingAsync(String input, Int32 repeatCount, String output)
[08:20:46] info:    at System.Security.Cryptography.Tests.Sha1Tests.Sha1_Rfc3174_3_Async()
[08:20:46] info: --- End of stack trace from previous location ---
[08:21:07] info: Finished:    System.Security.Cryptography.Tests.dll
[08:21:07] info: 
[08:21:07] info: === TEST EXECUTION SUMMARY ===
[08:21:07] info: Total: 1163, Errors: 0, Failed: 1, Skipped: 1, Time: 24.820985s

https://helixre8s23ayyeko0k025g8.blob.core.windows.net/dotnet-runtime-refs-pull-69786-merge-4202b33d23d54c99bd/WasmTestOnBrowser-System.Security.Cryptography.Tests/1/console.99f7714c.log?helixlogtype=result

[10:47:51] info: Starting:    System.Security.Cryptography.Tests.dll
[10:47:55] fail: [FAIL] System.Security.Cryptography.Tests.Sha256Tests.Sha256_Fips180_3
[10:47:55] info: Assert.Equal() Failure
[10:47:55] info:            ↓ (pos 0)
[10:47:55] info: Expected: [205, 199, 110, 92, 153, ...]
[10:47:55] info: Actual:   [156, 156, 59, 215, 224, ...]
[10:47:55] info:            ↑ (pos 0)
[10:47:55] info:    at System.Security.Cryptography.Tests.HashAlgorithmTestDriver.VerifyOneShotAllocatingStream(Stream input, String output)
[10:47:55] info:    at System.Security.Cryptography.Tests.HashAlgorithmTestDriver.VerifyRepeating(String input, Int32 repeatCount, String output)
[10:47:55] info:    at System.Security.Cryptography.Tests.Sha256Tests.Sha256_Fips180_3()
[10:47:55] info:    at System.Reflection.MethodInvoker.InterpretedInvoke(Object obj, Span`1 args, BindingFlags invokeAttr)
[10:48:00] fail: [out of order message from the browser]: http://127.0.0.1:35197/dotnet.js 2:70309 Uncaught
[11:02:46] fail: Application has finished with exit code TIMED_OUT but 0 was expected
XHarness exit code: 71 (GENERAL_FAILURE)
/datadisks/disk1/work/A6E90937/w/A157086B/e /datadisks/disk1/work/A6E90937/w/A157086B/e
----- end Wed May 25 11:02:46 UTC 2022 ----- exit code 71 ----------------------------------------------------------

Both of these tests are testing the hash of one million ASCII lowercase a characters.

Having run through hashes of {}, {'a'}, {'a', 'a'}, all the way up to 5 million, for both SHA-1 and SHA-2-256, I can’t reproduce either of these error values.

It seems like, somehow, bad data got into the pipeline… it’s not a case of too much, or too little.

Also noteworthy is that each of these failed in the allocating one-shots over streams (public static byte[] HashData(Stream), and the async variant), after successfully doing it via other methods.