asan: kernel: make no_sanitize("address") attribute work with -fsanitize=kernel-address

Summary:
Right now to disable -fsanitize=kernel-address instrumentation, one needs to use no_sanitize("kernel-address"). Make either no_sanitize("address") or no_sanitize("kernel-address")  disable both ASan and KASan instrumentation. Also remove redundant test.

Patch by Andrey Konovalov

Reviewers: eugenis, kcc, glider, dvyukov, vitalybuka

Reviewed By: eugenis, vitalybuka

Differential Revision: https://reviews.llvm.org/D44981

llvm-svn: 329612