compiler_wrapper: move llvm-next options to clang options

The new Clang version has a number of new warnings which we disable. This CL
makes those apply to llvm (current) as well as llvm-next.

BUG=None
TEST=go test

Change-Id: I1f4929580953003d21676e7e72af4577592fb217
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/2561725
Reviewed-by: Manoj Gupta <manojgupta@chromium.org>
Tested-by: Manoj Gupta <manojgupta@chromium.org>
Commit-Queue: Manoj Gupta <manojgupta@chromium.org>
36 files changed