Fix a few regression test failures (#222)

src/cmd/ksh93/tests/_common:
- Commit aed5c6d7 renamed the err_exit function,
  breaking a few tests in glob.sh that call the function
  directly instead of using the alias. Restore the function.

src/cmd/ksh93/tests/builtins.sh:
- The dtksh builtins don't have optget option parsing, so
  skip the unrecognized options test for those (this of
  course only has relevance when running dtksh against the
  regression tests).

src/cmd/ksh93/tests/pty.sh:
- If the vi editor couldn't be found on the $PATH, skip the
  regression test that involves it.

src/cmd/ksh93/tests/builtins.sh

@@ -963,7 +963,7 @@ EOF
 # Builtins should handle unrecognized options correctly
 while IFS= read -r bltin <&3
 do	case $bltin in
-	echo | test | true | false | \[ | : | getconf | */getconf | uname | */uname | login | newgrp)
+	echo | test | true | false | \[ | : | getconf | */getconf | uname | */uname | Dt* | X* | login | newgrp )
 		continue ;;
 	/*/*)	expect="Usage: ${bltin##*/} "
 		actual=$({ PATH=${bltin%/*}; "${bltin##*/}" --this-option-does-not-exist; } 2>&1) ;;