gn build: Port d090311aa7df

e60a69ab8a9e created a dependency on clangFrontend from clangDriver.
This broke the build of clang-offload-bundler because it only depends
on Driver (and only in debug builds, probably because the dependency was
dead code in clang-offload-bundler). Add the dependency to fix the build,
which also ports d090311aa7df from CMake.

GitOrigin-RevId: bb716c7d606934255366c3fdf4e335e868e2532c