Implement '==', '!=' and instanceof (without code generation).

tests/language/src/BoolTest.dart

Index: tests/language/src/BoolTest.dart
===================================================================
--- tests/language/src/BoolTest.dart	(revision 5111)
+++ tests/language/src/BoolTest.dart	(working copy)
@@ -105,8 +105,16 @@
     Expect.equals("false", false.toString());
   }
 
+  static void testNegate(isTrue, isFalse) {
+    Expect.equals(true, !false);
+    Expect.equals(false, !true);
+    Expect.equals(true, !isFalse);
+    Expect.equals(false, !isTrue);
+  }
+
   static void testMain() {
     testEquality();
+    testNegate(true, false);
     testToString();
   }
 }