Embed 64 bit constants directly in the IR, using two slots.

Contributed by Peter Cawley.

src/lj_opt_mem.c

@@ -22,8 +22,8 @@
 /* Some local macros to save typing. Undef'd at the end. */
 #define IR(ref)		(&J->cur.ir[(ref)])
 #define fins		(&J->fold.ins)
-#define fleft		(&J->fold.left)
-#define fright		(&J->fold.right)
+#define fleft		(J->fold.left)
+#define fright		(J->fold.right)
 
 /*
 ** Caveat #1: return value is not always a TRef -- only use with tref_ref().