[CMake] Add llvm-tblgen to dependencies of check-llvm.

llvm-tblgen is not built when external LLVM_TABLEGEN is specified.
Even then, llvm-tblgen should be built for testing tblgen itself.

llvm-svn: 199558
GitOrigin-RevId: 3189afc4ca436f6b56ddf1d6c989a3a96d9a1ab6
1 file changed