So far we've gotten away with using GCC 11 for Lagom and to compile the
toolchain, but via #15795 we discovered a compiler bug that has been
fixed in the latest version but would error the build with CI's GCC 11.
Time for an upgrade :^)
We already use ubuntu-22.04 images in most places, so this is pretty
straightforward. The only exception is Idan's self-hosted runner, which
uses Ubuntu Focal. LibJS should build fine with GCC 11, still.
This is no longer relevant for most users because due to an
unrelated change to Meta/run.sh the default display backend is now
SDL which does not exhibit this problem.
