[llvm] [BOLT] Enable lit internal shell by default (PR #156083)

[Hans Wennborg via llvm-commits]

zmodem wrote:

We're seeing `bolt/test/runtime/instrumentation-indirect-2.c` fail (hang) after this. (https://crbug.com/442483657)

I see it still has `REQUIRES: shell` but that doesn't seem to help:

https://github.com/llvm/llvm-project/blob/9a1e47839a331be303cb5b8ec034bfa53cc30f8a/bolt/test/runtime/instrumentation-indirect-2.c#L53

I don't see the failure on any of the bolt buildbots, but those bots don't seem to have built anything for months, e.g. https://lab.llvm.org/buildbot/#/builders/113/builds/8245 is the last build on bolt-x86_64-ubuntu-clang and it seems to be a month old.

We'll work around this by excluding the test from our builds for now, but it would be great if someone could look into it.

https://github.com/llvm/llvm-project/pull/156083