Auto merge of #47155 - nerd2:debuginfo_test_fix, r=alexcrichton
Restore working debuginfo tests by trimming comments from non-header directive lines
I noticed when adding a debuginfo test that nothing I did caused the test to fail. Tracing back this seems to have been caused by 3e6c83de1dc0a72df3663617d394a9e79641618d which broke parsing of the command/check lines, leaving all tests passing without any checking. This commit provides a basic (although still not very robust) restoration of tests and a should-fail test which checks the parser is running