test_gdb is skipped on the GitHub Action Ubuntu job, because gdb is not installed.

Would it be possible to install it?

I broke buildbots because I renamed the function "collect" to "gc_collect_main" in Modules/gcmodule.c and python-gdb.py uses it to check if Python is running a garbage collection. The strange thing is that test_gdb passed on Travis CI of my PR python/cpython#23038 test_gdb was skipped on the Ubuntu job.