Merge branch 'jc/fix-tap-output-under-bash'

A recent attempt to make the test output nicer to view on CI
systems broke TAP output under bash.  The effort has been reverted
to be re-attempted in the next cycle.

* jc/fix-tap-output-under-bash:
  Revert "tests: when run in Bash, annotate test failures with file name/line number"
  Revert "ci: add a problem matcher for GitHub Actions"
  Revert "t/test_lib: avoid naked bash arrays in file_lineno"