[libc++] Allow running the test suite with optimizations (#68753)

This patch adds a configuration of the libc++ test suite that enables
optimizations when building the tests. It also adds a new CI
configuration to exercise this on a regular basis. This is added in the
context of [1], which requires building with optimizations in order to
hit the bug.

[1]: https://github.com/llvm/llvm-project/issues/68552

GitOrigin-RevId: ca06c330fd07f05e65a638892c32ca1474d47b5e
3 files changed
tree: e550c97c86e6bd10d977d9fe9141967d5b2101e7
  1. cmake/
  2. docs/
  3. include/
  4. src/
  5. test/
  6. .clang-format
  7. CMakeLists.txt
  8. LICENSE.TXT