Enable skipped Runtime.Extensions tests on Android (#56586)

Enable skipped Runtime.Extensions tests on Android (#56586)

1. AppDomain TestingCreateInstanceFromObjectHandle and TestingCreateInstanceFromObjectHandleFullSignature were failing because the assembly file to load has to be case sensitive and wasn't.

2. AppDomain TargetFrameworkTest was permanently skipped

3. StringComparerTests CreateFromCultureAndOptions, CreateFromCultureAndOptionsStringSort, and CreateWithCulturesTest skips testing the turkish culture as it's problematic on Android

4. Environment.Exit ExitCode_VoidMainAppReturnsSetValue was permanently skipped

Fixes https://github.com/dotnet/runtime/issues/49868