Fix MSVC "compiler limit: blocks nested too deeply" error. NFCI.
Fix MSVC "compiler limit: blocks nested too deeply" error. NFCI.

MSVC only accepts if-else chains up to 127 blocks long. I've had to merge a number of intrinsic cases together to get back below this limit, resulting in some duplication of string matches; this shouldn't cause any notable increase in runtime (and even then only for old IR, nothing that clang currently emits).

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@339666 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm