Switching PPC/S390X over to Clang instead of GCC causes a handful of test failures. We should try to understand why to determine if its worth fixing.

Patch build - https://spruce.mongodb.com/version/68d106b3dc7bf30007a43ff3/tasks?page=0&sorts=STATUS%3AASC%3BBASE_STATUS%3ADESC 

As a heads up changing over to Clang did cause a few new warnings that you can see here - https://parsley.mongodb.com/evergreen/mongodb_mongo_master_nightly_enterprise_rhel_9_ppc64le_archive_dist_test_patch_04741d0a5defed5ae4f4c41bd1cc7b3d9ff3283e_68bf858ccdd97d0007a739b7_25_09_09_01_41_11/0/task?bookmarks=0,8772 - could be unrelated to the test failures though.