Our currently vendored MozJS version fails to build from source in C++20 mode. To work around this, we expect that SERVER-59230 will be resolved by including an override to continue to build the MozJS sources in C++17 mode, even when the overall build is opted in to C++20. As part of upgrading MozJS to a newer ESR, we should remove this override so that MozJS is compiled in the same mode as the rest of the codebase.