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

[James Henderson via llvm-commits]

jh7370 wrote:

> We do have long-term plans to address this issue with REQUIRES: shell, but I'm not sure what can be done in the short-term so that we don't lose coverage.

Don't enable the internal shell by default seems like a viable option to me...

Perhaps more helpfully, I think most (but probably not all, e.g. the color-diagnostics tests) of these tests can be modified to work with the internal shell without issue. In some cases, the only necessary modification may be removing the `REQUIRES: shell`. For example, I'm not sure why `./lld/test/wasm/reproduce.s` uses it: the majority of the commands in there are available in the internal shell, and the remainder (i.e. `tar`) are part of the minimum required tools, I believe. LLD has some tests that use tar without any REQUIRES, and others that have the `gnutar` requirement (the latter is presumably redundant, given that the former tests exist and pass fine).

We shouldn't enable the internal shell by default until we've got a clear migration path forward for all of these tests, preferably with them modified up front before the default change.

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