[runtimes] Reintroduce a way to select the compiler used for the test suite (#93542)

A while back, the cxx_under_test Lit parameter was removed. This patch
reintroduces a Lit parameter called "compiler" which controls the value
of the %{cxx} substitution used in the test suite.

To run the test suite with a different compiler, one can now pass
--param compiler=<path>.

NOKEYCHECK=True
GitOrigin-RevId: 633ea41b54bf7b2f10850bbd5ba3c4ab06081595
2 files changed
tree: 080c1f1f3c6892476809ccdf6118b7c6e25094c7
  1. cmake/
  2. docs/
  3. include/
  4. src/
  5. test/
  6. .clang-format
  7. CMakeLists.txt
  8. LICENSE.TXT