runtime: Vector128/256: Too many calls to "ThrowIfUnsupportedType" prevents inlining

I am trying to optimize certain generic helpers of Vector128/256<T> by HW intrinsic and other helpers, which relies on inlining to get the optimal codegen. However, sometimes these helpers cannot get inlined due to “inline exceeds budget” because too many ThrowIfUnsupportedType need to be eliminated by inlining. This issue may give users unexpected codegen when they heavily use generic Vector128/256<T> helpers (e.g., Count, GetLower, etc.) https://github.com/dotnet/coreclr/blob/10c3e60c863d01f638daa240af957c3c5791cda5/src/System.Private.CoreLib/shared/System/Runtime/Intrinsics/Vector256_1.cs#L342-L347 https://github.com/dotnet/coreclr/blob/10c3e60c863d01f638daa240af957c3c5791cda5/src/System.Private.CoreLib/shared/System/Runtime/Intrinsics/Vector256_1.cs#L78-L103

We need to find an approach to reduce the number of ThrowIfUnsupportedType call-site.

@CarolEidt @tannergooding @eerhardt @AndyAyersMS