Backport ksh93v- bugfix for [[ 1<2 ]] (#380)

Strings compared in [[ with the > and < operators should be compared
lexically. This does not work when the strings are single digits, as
the parser interprets it as a syntax error:
   $ [[ 10<2 ]]   # 10 lexically sorts before 2
   $ echo $?
   0
   $ [[ 1<2 ]]
   /usr/bin/ksh: syntax error: `<' unexpected
   $ echo $?
   3

src/cmd/ksh93/sh/lex.c:
- Don't interpret numbers next to > and < as a redirection while
  inside of [[. This bugfix was backported from ksh93v- 2014-06-25.

src/cmd/ksh93/tests/bracket.sh:
- Add regression tests for the > and < operators.

src/cmd/ksh93/sh/lex.c

@@ -1264,7 +1264,7 @@ breakloop:
 	{
 		/* check for numbered redirection */
 		n = state[0];
-		if((c=='<' || c=='>') && isadigit(n))
+		if(!lp->lex.intest && (c=='<' || c=='>') && isadigit(n))
 		{
 			c = sh_lex(lp);
 			lp->digits = (n-'0');