This reverts commit 97aa593a83 as it
causes problems (PR45453) https://reviews.llvm.org/D77574#1966321.
This additionally adds an explicit reference to FrontendOpenMP to
clang-tidy where ASTMatchers is used.
This is hopefully just a temporary solution. The dependence on
`FrontendOpenMP` from `ASTMatchers` should be handled by CMake
implicitly, not us explicitly.
Reviewed By: aheejin
Differential Revision: https://reviews.llvm.org/D77666
f9d558c871