[Sema][X86] Consider target attribute into the checks in validateOutputSize and valid...

[Sema][X86] Consider target attribute into the checks in validateOutputSize and validateInputSize.

The validateOutputSize and validateInputSize need to check whether
AVX or AVX512 are enabled. But this can be affected by the
target attribute so we need to factor that in.

This patch copies some of the code from CodeGen to create an
appropriate feature map that we can pass to the function. Probably
need some refactoring here to share more code with Codegen. Is
there a good place to do that? Also need to support the cpu_specific
attribute as well.

Differential Revision: https://reviews.llvm.org/D68627