Checking in on behalf of PeterSol to fix the rolling build:

As Ati noticed, my fix for issue 433565 causes a regression because if the actual type is not a DefType, the cast to DefType obviously fails.

I believe that in this case the type can also not be a nullable type, so one possible way to fix this is to test for the case where the type is not a DefType, and treat it the same way as FixupSignatureKind.TypeHandle if it is not.

[tfs-changeset: 1659248]

Merge changes from TFS

…tionaries.

     The naming and exporting of method generic dictionaries are differnt from method entries. They have their own oridinals in the TOC files. Actually, method that has generic dictionaries are implemented by shared code, so its entry should not be in the TOC files. This change seperates the handling of method generic dictionaries from method entries and ensure they get a unique and consistent name between the compilation of shared library and an app.

     This change also moves the UTC symbol attribute abstraction (such as isInModule, isDirectReference, isExport ...) upwards to the JIT interface so that we no longer use a method handle for every method-related query or type handle for every type-related query. Also, in this way UTC does not need to know how to handle differnt types of symbols specifically. It will generally call SetPNSymbolAttributes with type system returned attributes on almost all symbols

[tfs-changeset: 1659289]

Merge changes from TFS

The prior commit added some runtime assertions for
conditions that we were taking new dependencies on.

This commits replaces those assertions with more
specific type declarations so all this can be enforced
at compile-time.

Make Marshal.PtrToStringAnsi() and StringToCoTaskMemAnsi()
and StringToHGlobalAnsi() work the same way CoreCLR/Desktop
does.

CR: SergeyK

Use normal (non-thread pool) threads to execute long-running tasks — as we do in CoreCLR.  Using thread pool threads caused starvation if other thread pool threads were busy working.  For instance, the
     ItemThreadSafetyTests.TestGetItemThreadSafety test in QA\ToF\tests\FX\Conformance\System.Collections.NonGeneric\4.0.0.0\Hashtable\HashtableTests.csproj creates 7 long-running tasks and would hang on a computer with only 4 logical cores.

[tfs-changeset: 1659419]

Merge changes from TFS

Sets things up for System.Runtime.Extensions.Tests bringup
on ILC.

Creates platform-specific EnvironmentAugments files.

Move GetEnvironmentVariable() over to EnvironmentAugments
(not used within CoreLib.)

Get of rid of emasculated UWP version and make it
use regular Windows version.

This is to support NetStandard APIs that are useful for CoreFX test bringup and general compat.

[tfs-changeset: 1659572]

Merge changes from TFS

Make Module.Name work off metadata.

Merge master to nmirror