hundreds failures failed with Assert.True() Failure

[v-haren]

hundreds failures failed in job: runtime 20201215.47
runtime-coreclr libraries-jitstress 20201214.2

Error message

Assert.True() Failure
Expected: True
Actual:   False

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Issue Details

---

hundreds failures failed in job: runtime 20201215.47
runtime-coreclr libraries-jitstress 20201214.2

Error message

Assert.True() Failure
Expected: True
Actual:   False

<table>
  <tr>
    <th align="left">Author:</th>
    <td>v-haren</td>
  </tr>
  <tr>
    <th align="left">Assignees:</th>
    <td>-</td>
  </tr>
  <tr>
    <th align="left">Labels:</th>
    <td>

`JitStress`, `area-System.Data`, `untriaged`

</td>
  </tr>
  <tr>
    <th align="left">Milestone:</th>
    <td>-</td>
  </tr>
</table>
</details>

[BruceForstall]

~/work/B0D409B2/w/AE2A0976/e ~/work/B0D409B2/w/AE2A0976/e
  Discovering: System.Runtime.Serialization.Xml.ReflectionOnly.Tests (method display = ClassAndMethod, method display options = None)
  Discovered:  System.Runtime.Serialization.Xml.ReflectionOnly.Tests (found 239 test cases)
  Starting:    System.Runtime.Serialization.Xml.ReflectionOnly.Tests (parallel test collections = on, max threads = 2)
    DataContractSerializerTests.DCS_GenericDictionaryOfStringInt32 [FAIL]
      Assert.True() Failure
      Expected: True
      Actual:   False
    DataContractSerializerTests.DCS_GenericDictionaryOfInt32String [FAIL]
      Assert.True() Failure
      Expected: True
      Actual:   False
      Stack Trace:
        /_/src/libraries/System.Runtime.Serialization.Xml/tests/DataContractSerializer.cs(2549,0): at DataContractSerializerTests.DCS_GenericDictionaryOfInt32String()

[AndyAyersMS]

Seems likely this was fallout from #46172, both test legs have since recovered to more "normal" failure rates.