clang packaging/win: Stop copying sanitizer headers to include_sanitizer directory.

Back when we were using /fallback on the asan bots, we had to add this
to the include_dir search path so that the fallback cl.exe compiler would find
asan headers as well, as it doesn't know about clang's built-in headers -- and
we couldn't add the path to clang's builtin headers as include_dir since that
would've also overriden things link stddef.h -- so we made a copy of the
builtin include dir that contained only the sanitizer directory as subdirectory.

We haven't used /fallback in years, this is no longer needed.

Effectively reverts https://codereview.chromium.org/281413006

Bug: 82385,345874
Change-Id: I9a56e17682a9a4a62815d22ad8fa67e8398b21fb
Reviewed-on: https://chromium-review.googlesource.com/582567
Reviewed-by: Hans Wennborg <hans@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#488956}
2 files changed