Fixed constant folding in HMod.

test/mjsunit/constant-folding-2.js

Index: test/mjsunit/constant-folding-2.js
diff --git a/test/mjsunit/constant-folding-2.js b/test/mjsunit/constant-folding-2.js
index 6dbb4abebf2fa9bcda716d3b7e263468e1d08ab1..4c50e30d548110f8b7984bdea2e3ee55df205548 100644
--- a/test/mjsunit/constant-folding-2.js
+++ b/test/mjsunit/constant-folding-2.js
@@ -256,3 +256,12 @@ test(function stringCharAt() {
   assertEquals("b", "abc".charAt(1.1));
   assertEquals("", "abc".charAt(4.1));
 });
+
+
+test(function int32Mod() {
+  assertEquals(-0, -2147483648 % (-1));
+});
+
+test(function int32Div() {
+  assertEquals(2147483648, -2147483648 / (-1));
+});