[clang] [clang][test] Rebuild lld if the clang driver tests will use it (PR #174512)

[Ian Anderson via cfe-commits]

ian-twilightcoder wrote:

> Looks good. Thinking along the lines that Cyndy is, should the support for lld/lto be captured in a resource so we can clean up the `REQUIRE:`/`UNSUPPORTED:` lines in the test cases?

If somebody else wants to do that, sure 😃. I think this is @abrachet's test?

https://github.com/llvm/llvm-project/pull/174512