Updating CreateScalar to be intrinsic for Vector64/128/256

[tannergooding]

This ensures that vector constant nodes can be created and improves the codegen for inserts involving float.

Handling for Create(Vector128<T> lower, Vector128<T> upper) also needs to be done, but will be a separate PR.

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Issue Details

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This ensures that vector constant nodes can be created and improves the codegen for inserts involving float.

Handling for Create(Vector128<T> lower, Vector128<T> upper) also needs to be done, but will be a separate PR.

Author:	tannergooding
Assignees:	tannergooding
Labels:	area-CodeGen-coreclr
Milestone:	-

[tannergooding]

CC. @dotnet/jit-contrib

[tannergooding]

/azp run runtime-coreclr jitstress-isas-x86, runtime-coreclr jitstress-isas-arm, runtime-coreclr outerloop

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[tannergooding]

outerloop failures are:

• Test failure GC/LargeMemory/Regressions/largearraytest/largearraytest.sh #77477
• Test failure baseservices\exceptions\simple\ParallelCrashWorkerThreads\ParallelCrashWorkerThreads.cmd #77791
• Test failure baseservices\exceptions\simple\ParallelCrashMainThread\ParallelCrashMainThread.cmd #77790

[EgorBo]

LGTM, assuming the test failures aren't related modulo the GT_CAST question.
Also, I assume it doesn't break mono since it converts a helper method into a "recursive" intrinsic

[tannergooding]

CI failures are currently dotnet/arcade#11554. However, there is no way to tell if its masking actual issues or not so I'll hold off on merging.