[libunwind][test] Add check for objcopy to improve test compatibility (#161112)

Previously, we only used `objcopy`, which is not available for some
build configurations. With this patch, we not only try to use `objcopy`,
but also try to use `llvm-objcopy` if available.

This is a follow-up of https://github.com/llvm/llvm-project/pull/156383.

GitOrigin-RevId: 4aaf6d1b8cc655f37a1a4ab8f7a7988dbef4eeae
2 files changed
tree: 230201e9cb4a24d57398a0514a6a4b15e8a59ed9
  1. cmake/
  2. docs/
  3. include/
  4. src/
  5. test/
  6. .clang-format
  7. CMakeLists.txt
  8. LICENSE.TXT