ci: remove gnu-getopt usage

This is used for argument parsing in the retry script, however we don't
use the script with any arguments. So remove the unused code, and the
dependency on gnu-getopt.

This came up in the context of adding new CI jobs, where gnu-getopt
might not be available, or working properly. It seemed easier to just
remove the unused code, than look for more workarounds.

ci/test/02_run_container.py

@@ -58,14 +58,6 @@ def main():
 
         # Modify PATH to prepend the retry script, needed for CI_RETRY_EXE
         os.environ["PATH"] = f"{os.environ['BASE_ROOT_DIR']}/ci/retry:{os.environ['PATH']}"
-        # GNU getopt is required for the CI_RETRY_EXE script
-        if os.getenv("CI_OS_NAME") == "macos":
-            prefix = run(
-                ["brew", "--prefix", "gnu-getopt"],
-                stdout=subprocess.PIPE,
-                text=True,
-            ).stdout.strip()
-            os.environ["IN_GETOPT_BIN"] = f"{prefix}/bin/getopt"
     else:
         CI_IMAGE_LABEL = "bitcoin-ci-test"