Replace -mllvm -asan-use-after-scope=1 with -fsanitize-address-use-after-scope

Summary:
When test was added we had no -fsanitize-address-use-after-scope in clang
so we had to use -mllvm -asan-use-after-scope=1.

Reviewers: eugenis

Subscribers: kubabrecka

Differential Revision: https://reviews.llvm.org/D22382

llvm-svn: 275475