Update dependencies from dotnet/corefx (dotnet/coreclr#27431)

* Update dependencies from https://github.com/dotnet/corefx build 20191024.13

- Microsoft.NETCore.Platforms - 5.0.0-alpha.1.19524.13
- Microsoft.Private.CoreFx.NETCoreApp - 5.0.0-alpha.1.19524.13

* Update dependencies from https://github.com/dotnet/corefx build 20191024.14

- Microsoft.NETCore.Platforms - 5.0.0-alpha.1.19524.14
- Microsoft.Private.CoreFx.NETCoreApp - 5.0.0-alpha.1.19524.14

* Update dependencies from https://github.com/dotnet/corefx build 20191025.6

- Microsoft.NETCore.Platforms - 5.0.0-alpha.1.19525.6
- Microsoft.Private.CoreFx.NETCoreApp - 5.0.0-alpha.1.19525.6

* Workaround https://github.com/dotnet/coreclr/issues/27465

Signed-off-by: dotnet-bot <dotnet-bot@microsoft.com>

src/System.Private.CoreLib/shared/Interop/Unix/System.Native/Interop.GetTimestamp.cs

@@ -12,7 +12,7 @@ internal static partial class Sys
         internal static extern ulong GetTimestampResolution();
 
         [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_GetTimestamp", ExactSpelling = true)]
-        [SuppressGCTransition]
+        // [SuppressGCTransition] // https://github.com/dotnet/coreclr/issues/27465
         internal static extern ulong GetTimestamp();
     }
 }