Move llvm util dependencies from clang-tools-extra to add_lit_target.

Summary:
Address fixme in r301762. And would simplify the cmake file in
clang-tools-extra.

Reviewers: sammccall

Subscribers: mgorny, llvm-commits, cfe-commits

Differential Revision: https://reviews.llvm.org/D52713

llvm-svn: 343473