[libunwind] Add a from-scratch config for running libunwind tests
Running tests for libunwind is a lot simpler than running tests for
libc++, so a simple Lit config file is sufficient. The benefit is that
we disentangle the libunwind test configuration from the libc++ and
libc++abi test configuration. The setup was too complicated, which led
to some bugs (notably we were running against the system libunwind on
Apple platforms).
Differential Revision: https://reviews.llvm.org/D111664
GitOrigin-RevId: 6fd55bba61bb4df98f9485b8d3cfc9e956d992b8
10 files changed
