[Support, ARM64] Define getHostCPUFeatures for Windows on ARM64 platform
[Support, ARM64] Define getHostCPUFeatures for Windows on ARM64 platform

Patch by Adam Kallai!

Differential Revision: https://reviews.llvm.org/D68139

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@373445 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm