Make FileCheck be a common dependency, not an ASan one.

Summary:
It still gets picked up by ASan, but it also gets picked up by the other
test suites.

Otherwise, some test suites (e.g: UBSan) would complain they had no
dependencies, and wouldn't run.

Reviewers: samsonov, eugenis

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7740

llvm-svn: 229962