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.right

@@ -1,5 +1,7 @@
 bash: -c: line 1: unexpected EOF while looking for matching `)'
+	parser1.sub
 AAA
+	posix2syntax.sub
 bash5: line 1: `invalid-name': not a valid identifier
 in
 in