Some fixes for the interpreter (dotnet/coreclr#19678)

Some fixes for the interpreter (dotnet/coreclr#19678)

A number of fixes to the interpreter so it can run many pri0 basic tests.

* fix build break
* fix new array
* fix small struct return assert
* implement must-expand `ByReference<T>` intrinsics
* add some missing null checks
* fix `stobj` type check assert
* basic SIMD support
* obey `COMPlus_FeatureSIMD` setting

HW Intrinsics are still not supported / implemented.

Commit migrated from https://github.com/dotnet/coreclr/commit/41f67dba85067e7c7c72b316a2cf29a4ec7d1e15