[libunwind] Tidy-up the testing configuration for libunwind

Start testing Apple backdeployment with older libunwinds, and stop
explicitly specifying the libunwind testing config, since it is
already selected correctly by default.

Differential Revision: https://reviews.llvm.org/D126470

GitOrigin-RevId: 92bbcfaa97408991813fda5c56e864c629f67a01
3 files changed
tree: e8bdfbed211cecd66253f197b247010007e1f86e
  1. cmake/
  2. docs/
  3. include/
  4. src/
  5. test/
  6. .clang-format
  7. CMakeLists.txt
  8. LICENSE.TXT