Merge pull request #7945 from ramarag/MemoryFailPoint

Disabling checks in MemoryFailPoint for Xplat

diff --cc src/mscorlib/src/System/Runtime/MemoryFailPoint.cs
index f04456b,1f0ea8c..c22ce65
--- 1/src/mscorlib/src/System/Runtime/MemoryFailPoint.cs
--- 2/src/mscorlib/src/System/Runtime/MemoryFailPoint.cs
+++ b/src/mscorlib/src/System/Runtime/MemoryFailPoint.cs
@@@ -157,9 -157,10 +157,10 @@@ namespace System.Runtim
          public MemoryFailPoint(int sizeInMegabytes)
          {
              if (sizeInMegabytes <= 0)
 -                throw new ArgumentOutOfRangeException("sizeInMegabytes", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
 +                throw new ArgumentOutOfRangeException(nameof(sizeInMegabytes), Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
              Contract.EndContractBlock();
  
+ #if !FEATURE_PAL // Remove this when CheckForAvailableMemory is able to provide legitimate estimates
              ulong size = ((ulong)sizeInMegabytes) << 20;
              _reservedMemory = size;