Opened on behalf of @JiayiLi1

The test System.SpanTests.SpanTests/CopyToLargeSizeTest(bufferSize: 4294967296) has failed.

System.OverflowException : Arithmetic operation resulted in an overflow.

    Stack Trace:

       at System.IntPtr.op_Explicit(Int64 value)
   at System.SpanTests.SpanTests.CopyToLargeSizeTest(Int64 bufferSize)

Build : Master - 20170418.01 (Core Tests)
Failing configurations:

• Windows.10.Amd64
  • x86-Debug
  • x86-Release
• Windows.7.Amd64
  • x86-Debug
  • x86-Release
• Windows.81.Amd64
  • x86-Debug
  • x86-Release

Detail: https://mc.dot.net/#/product/netcore/master/source/official~2Fcorefx~2Fmaster~2F/type/test~2Ffunctional~2Fcli~2F/build/20170418.01/workItem/System.Memory.Tests/analysis/xunit/System.SpanTests.SpanTests~2FCopyToLargeSizeTest(bufferSize:%204294967296)