Try fixing the generated files job

Author: ldionne

.github/workflows/libcxx-check-generated-files.yml

@@ -23,5 +23,5 @@ jobs:
       - name: Check generated files
         run: libcxx/utils/ci/run-buildbot check-generated-output
         env:
-          CC: clang-22
-          CXX: clang++-22
+          CC: cc
+          CXX: c++