Implement OP_JMPLFB & OP_JMPLFE VM instructions.

include/ph7int.h

@@ -1399,6 +1399,8 @@ enum ph7_vm_op {
 	PH7_OP_JMP,          /* Unconditional jump */
 	PH7_OP_JMPZ,         /* Jump on zero (FALSE jump) */
 	PH7_OP_JMPNZ,        /* Jump on non-zero (TRUE jump) */
+	PH7_OP_JMPLFB,       /* Jump loop frame begin */
+	PH7_OP_JMPLFE,       /* Jump loop frame end */
 	PH7_OP_POP,          /* Stack POP */
 	PH7_OP_CVT_INT,      /* Integer cast */
 	PH7_OP_CVT_STR,      /* String cast */