[clang-tools-extra] [clangd][test] Add `clang` to `CLANGD_TEST_DEPS`. (PR #230061)

[Ingo Müller via cfe-commits]

ingomueller-net wrote:

Good point about the dependency increase. I have no insight about what is acceptable here. I'll let other people decide.

https://github.com/llvm/llvm-project/pull/230061