tests/variables.sh: update virtual subshell failure TODO

Namerefs aren't broken in virtual/non-forked subshells after all
(phew). It is changing the locale that is somehow broken.

src/cmd/ksh93/tests/variables.sh:
- Pending further investigation, update the TODO and don't fork the
  subshell until actually needed.

(cherry picked from commit efa3150396b383b6a68b2df45eab9005593b2e42)

src/cmd/ksh93/tests/variables.sh

@@ -629,10 +629,6 @@ set -- {1..32768}
 set --
 
 (
-	# TODO: namerefs are broken in non-forked/virtual subshells.
-	# For now, fork it using ulimit; remove the ulimit to expose the test failures.
-	ulimit -t unlimited
-
 	unset r v x
 	x=foo
 	for v in EDITOR VISUAL OPTIND CDPATH FPATH PATH ENV LINENO RANDOM SECONDS _
@@ -646,6 +642,9 @@ set --
 		fi
 	done
 
+	# TODO: changing the locale is somehow broken in non-forked/virtual subshells.
+	# For now, fork it using ulimit; remove the ulimit to expose the test failures.
+	ulimit -t unlimited
 	x=x
 	for v in LC_ALL LC_CTYPE LC_MESSAGES LC_COLLATE LC_NUMERIC
 	do	nameref r=$v