This is a revert of b1fcc1840c312472cb9ccb8c4e5e02ca13b31113. These tests weren't working on Ubuntu 22.04 or Fedora 37-40. I'm not sure exactly why, but it seems like they may be incompatible with libstdc++. Also, despite the fact that the tests were using the system libstdc++, the tests were only run when libcxx was enabled. I tested this with a RelWithDebInfo build and the tests passed. Fixes #106475