hush: tighten up "for" variable name check.

Add TODOs.
 Disable redir4.right part where we differ from bash.
 It is not a bug per standards.
 Add a few tests, one is in hush-bugs section:
 and_or_and_backgrounding.right. It will likely bite users
 in real world usage.

shell/hush_test/hush-misc/redir4.tests

@@ -38,7 +38,7 @@ Here4
 echo Ok4
 
 
-echo How with variable refs
+echo Now with variable refs
 i=1
 
 
@@ -58,6 +58,11 @@ rm *shell_test*
 echo *shell_test*
 rm *shell_test*
 
+echo Done;exit
+# UNFIXED BUG. bash apparently will expand $i even in terminating delimiter.
+# http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html
+# does not mandate this behavior.
+# This is not likely to be used much in real-world.
 
 cat <<\shell_test_$i
 Here1