JIT: Fix register allocation

Fixes oss-fuzz #45487

Author: dstogov

ext/opcache/jit/zend_jit_x86.dasc

@@ -15982,6 +15982,7 @@ static zend_regset zend_jit_get_scratch_regset(const zend_op *opline, const zend
 			    !(op2_info & ((MAY_BE_ANY|MAY_BE_REF|MAY_BE_UNDEF)-MAY_BE_LONG))) {
 				regset = ZEND_REGSET_EMPTY;
 				if (opline->op2_type == IS_CONST &&
+				    opline->op1_type != IS_CONST &&
 				    Z_TYPE_P(RT_CONSTANT(opline, opline->op2)) == IS_LONG &&
 				    zend_long_is_power_of_two(Z_LVAL_P(RT_CONSTANT(opline, opline->op2))) &&
 				    OP1_HAS_RANGE() &&

ext/opcache/tests/jit/reg_alloc_013.phpt

@@ -0,0 +1,19 @@
+--TEST--
+Register Alloction 013: Division by zero
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.file_update_protection=0
+opcache.jit_buffer_size=1M
+--FILE--
+<?php
+function foo() {
+    $j++;
+    $j++ % $j -= $a % $a = $j;
+}
+foo();
+?>
+DONE
+--EXPECTF--
+Warning: Undefined variable $j in %sreg_alloc_013.php on line 3
+DONE