[clang-tidy] Fix linking tests to LLVMTestingSupport

LLVMTestingSupport is not part of libLLVM, and therefore can not
be linked to via LLVM_LINK_COMPONENTS.  Instead, it needs to be
specified explicitly to ensure that it is linked explicitly
even if LLVM_LINK_LLVM_DYLIB is used.  This is consistent with handling
in clangd.

Fixes PR#48931

Differential Revision: https://reviews.llvm.org/D95653