test suite updates: highlight failed test scripts; optionally save failed test output; report number of successful tests; exit based on number of test failures; indent warning messages to make them stand out

tests/parser.tests

@@ -1,4 +1,5 @@
 # catch-all for parsing problems that don't fit anywhere else
+. ./test-aux-functions
 
 # word_top issues in bash-5.2
 case x in x) if ((1)); then :; fi ;; esac
@@ -11,6 +12,6 @@ case x in x) if ((true ) ); then :; fi esac
 ${THIS_SH} -c '((X=([))]' bash
 
 # this has to be in a separate file to get desired EOF behavior
-${THIS_SH} ./parser1.sub
+test_runsub ./parser1.sub
 
-${THIS_SH} ./posix2syntax.sub
+test_runsub ./posix2syntax.sub