Set supported target for asan-use-callbacks test

Explicitely set x86_64-linux-gnu as a target for asan-use-callbacks
clang test since some target do not support -fsanitize=address (e.g.
i386-pc-openbsd). Also remove redundant -fsanitize=address and move
-emit-llvm right after -S.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D107633