Revert "[clang-tidy] Add use-nullptr check to clang-tidy."

The new test is failing on darwin:

http://lab.llvm.org:8080/green/job/clang-stage1-configure-RA_check/10339/

This reverts r245434 and its follow up r245471.

llvm-svn: 245493
GitOrigin-RevId: 71e1a579b2632338631bd1869e88559b7b12754d
6 files changed