Add another test for JS semantics. (range propagation).

tests/compiler/dart2js_extra/constant_javascript_semantics3_test.dart

Index: tests/compiler/dart2js_extra/constant_javascript_semantics3_test.dart
diff --git a/tests/compiler/dart2js_extra/constant_javascript_semantics2_test.dart b/tests/compiler/dart2js_extra/constant_javascript_semantics3_test.dart
similarity index 56%
copy from tests/compiler/dart2js_extra/constant_javascript_semantics2_test.dart
copy to tests/compiler/dart2js_extra/constant_javascript_semantics3_test.dart
index af4872fd2b066b46cfd00062dfb04b78f0bc6771..b21674d2bac51a93a7232318dc4d8ac0177c2202 100644
--- a/tests/compiler/dart2js_extra/constant_javascript_semantics2_test.dart
+++ b/tests/compiler/dart2js_extra/constant_javascript_semantics3_test.dart
@@ -6,16 +6,28 @@
 // In this case we test that the value-range analysis uses JavaScript semantics
 // too.
 
-int inscrutable(int x) => x == 0 ? 0 : x | inscrutable(x & (x - 1));
+int inscrutable(int x) {
+  if (x == 0) return 0;
+  return x | inscrutable(x & (x - 1));
+}
 
 foo() {
-  var a = const [1, 2];
-  var i = 0x100000000;
+  var a = const [1, 2, 3, 4];
+  var i = 8007199254740992;
   if (inscrutable(i) == 0) {
-    i = 0x100000001;
+    i++;
   }
-  i = 0xFFFFFFFFF & i;  // In JS semantics [:i:] will be truncated to 32 bits.
-  i = 0x100000001 - i;
+  i += 1000000000000000;
+  // [i] is now at its maximum 53 bit value. The following increments will not
+  // have any effect.
+  i++;
+  i++;
+  i++;
+  i -= 1000000000000000;
+  i--;
+  i--;
+  i--;
+  i -= 8007199254740992;   // In JS semantics [i] would be -3, now.
   return a[i];
 }