CheckForMismatchingPlatform should log the RuntimeIdentifier and PlatformTarget on error

[eerhardt]

I've run into a situation where I get this error:

/home/eerhardt/git/source-build/src/vstest/tools/dotnet/sdk/2.0.0-preview3-006845/Sdks/Microsoft.NET.Sdk/build/Microsoft.NET.RuntimeIdentifierInference.targets(125,5): error : The RuntimeIdentifier platform and the PlatformTarget must match. [/home/eerhardt/git/source-build/src/vstest/src/testhost.x86/testhost.x86.csproj] [/home/eerhardt/git/source-build/targets/repository.proj]

This is coming from this code:

sdk/src/Tasks/Microsoft.NET.Build.Tasks/build/Microsoft.NET.RuntimeIdentifierInference.targets

Lines 121 to 128 in 98ea6b2

	<Target Name="_CheckForMismatchingPlatform"
	BeforeTargets="_CheckForInvalidConfigurationAndPlatform"
	Condition="'$(RuntimeIdentifier)' != '' and '$(PlatformTarget)' != ''">
	<NETSdkError Condition="'$(PlatformTarget)' != 'AnyCPU' and !$(RuntimeIdentifier.ToUpper().Contains($(PlatformTarget.ToUpper())))"
	ResourceName="CannotHaveRuntimeIdentifierPlatformMismatchPlatformTarget" />
	</Target>

It would be helpful if this error would log what the $(RuntimeIdentifier) and $(PlatformTarget) values where, in order to help users debug what went wrong in their builds.