Fix for issue 10534. Implement int.pow correctly. Note that int.pow is considerably slower than dou…

tests/standalone/pow_test.dart

Index: tests/standalone/pow_test.dart
===================================================================
--- tests/standalone/pow_test.dart	(revision 22629)
+++ tests/standalone/pow_test.dart	(working copy)
@@ -85,14 +85,23 @@
 void main() {
   int exp = 0;
   for (int val in expectedResults) {
-    Expect.equals(val, pow(2, exp++));
+    Expect.equals(val, pow(2, exp));
+    Expect.equals(val.toDouble(), pow(2, exp.toDouble()));
+    exp++;
   }
+
   // Optimize it.
   for (int i = 0; i < 8888; i++) {
     pow(2, 3);
+    pow(2.0, 3.0);
   }
   exp = 0;
   for (int val in expectedResults) {
-    Expect.equals(val, pow(2, exp++));
+    Expect.equals(val, pow(2, exp));
+    Expect.equals(val.toDouble(), pow(2, exp.toDouble()));
+    exp++;
   }
+  // Test Bigints.
+  Expect.equals(5559917313492231481, pow(11, 18));
+  Expect.equals(672749994932560009201, pow(11, 20));
 }