Changes

[clang-format] [RELAND] Remove the dependency on frontend
Summary: relanding {D68969} after it failed UBSAN build caused by the
passing of an invalid SMLoc() (nullptr)
Reviewers: thakis, vlad.tsyrklevich, klimek, mitchell-stellar
Reviewed By: thakis
Subscribers: merge_guards_bot, mgorny, cfe-commits
Tags: #clang-format, #clang
Differential Revision: https://reviews.llvm.org/D69854