Bug: wrong code gen. for indices with comparisons

In function 'luaK_exp2val', used to generate code for indices: Macro
'hasjumps' does not consider the case when the whole expression is a
"jump" (a test). In all other of its uses, the surrounding code ensures
that the expression cannot be VJMP.

lcode.c

@@ -31,6 +31,7 @@
 #include "lvm.h"
 
 
+/* (note that expressions VJMP also have jumps.) */
 #define hasjumps(e)	((e)->t != (e)->f)
 
 
@@ -991,7 +992,7 @@ void luaK_exp2anyregup (FuncState *fs, expdesc *e) {
 ** or it is a constant.
 */
 void luaK_exp2val (FuncState *fs, expdesc *e) {
-  if (hasjumps(e))
+  if (e->k == VJMP || hasjumps(e))
     luaK_exp2anyreg(fs, e);
   else
     luaK_dischargevars(fs, e);