Let asan imply clang and use_allocator=none.
Let asan imply clang and use_allocator=none.

BUG=

Review URL: https://codereview.chromium.org/1089393004

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#27905}

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh