Silence a few warnings within the LLVM code used by Subzero
which ended up being treated as errors when compiling
Chromium for x86.

Change-Id: If4d3c13ce0b01185d59a2cd064b2bad537639b94
Reviewed-on: https://swiftshader-review.googlesource.com/8813Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>