This change implements getHostCPUFeatures function to enable this functionality on Windows on ARM64.
This was committed to llvm at https://reviews.llvm.org/D68139 .

Bug: chromium:893460
Change-Id: I7ae62f298683979a4ab1aa8099d6e91706b15c9b
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/37328
Presubmit-Ready: Alexis Hétu <sugoi@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Tested-by: Alexis Hétu <sugoi@google.com>