[llvm] [lit] Support wildcard in --xfail-not option (PR #151191)

[Joel E. Denny via llvm-commits]

jdenny-ornl wrote:

> IIUC you're saying it's possible that when turning `--xfail-not=*` and profcheck, some of the resulting failures aren't due to profcheck (either now or in the future).

Right.  Regardless of profcheck, tests that are already marked XFAIL might be failing places other than FileCheck, so `--xfail-not=*` will convert them from expected fails to unexpected fails.

> That's fine - we can piecemeal mark those tests as unsupported when profcheck is enabled.

For profcheck, is it really worthwhile to run tests that are currently expected to fail?  Maybe a more complete solution than `--xfail-not=*` would be a flag that tells lit to skip tests that are marked xfail.  Maybe `--skip-xfail`.

https://github.com/llvm/llvm-project/pull/151191