[lld] [lld][llvm-lit] Enabled lit internal shell for lld test suite (PR #106651)

[James Henderson via llvm-commits]

jh7370 wrote:

How many tests have `REQUIRES: shell` in the lld testsuite? I have real concerns that we'll end up with tests that are NEVER enabled, because nobody is going to explicitly specify to use the external shell.

https://github.com/llvm/llvm-project/pull/106651