Reapply change to update dart2js operator equals semantics to follow

lib/compiler/implementation/lib/js_helper.dart

Index: lib/compiler/implementation/lib/js_helper.dart
diff --git a/lib/compiler/implementation/lib/js_helper.dart b/lib/compiler/implementation/lib/js_helper.dart
index 4f45b395ec5451d57e4aebb0d1dc37cba7e34c12..1027a46bae0699588e200b47cc0e574c0affbd01 100644
--- a/lib/compiler/implementation/lib/js_helper.dart
+++ b/lib/compiler/implementation/lib/js_helper.dart
@@ -171,12 +171,11 @@ tdiv(var a, var b) {
 }
 
 eq(var a, var b) {
-  if (JS('bool', @"# == null", a)) return JS('bool', @"# == null", b);
+  if (JS('bool', @'# == null', a)) return JS('bool', @'# == null', b);
+  if (JS('bool', @'# == null', b)) return false;
   if (JS('bool', @'typeof # === "object"', a)) {
     if (JS_HAS_EQUALS(a)) {
       return UNINTERCEPTED(a == b);
-    } else {
-      return JS('bool', @'# === #', a, b);
     }
   }
   // TODO(lrn): is NaN === NaN ? Is -0.0 === 0.0 ?
@@ -184,12 +183,11 @@ eq(var a, var b) {
 }
 
 bool eqB(var a, var b) {
-  if (JS('bool', @"# == null", a)) return JS('bool', @"# == null", b);
+  if (JS('bool', @'# == null', a)) return JS('bool', @'# == null', b);
+  if (JS('bool', @'# == null', b)) return false;
   if (JS('bool', @'typeof # === "object"', a)) {
     if (JS_HAS_EQUALS(a)) {
       return UNINTERCEPTED(a == b) === true;
-    } else {
-      return JS('bool', @'# === #', a, b);
     }
   }
   // TODO(lrn): is NaN === NaN ? Is -0.0 === 0.0 ?
@@ -200,26 +198,6 @@ eqq(var a, var b) {
   return JS('bool', @'# === #', a, b);
 }
 
-eqNull(var a) {
-  if (JS('bool', @'# == null', a)) return true;
-  if (JS('bool', @'typeof # === "object"', a)) {
-    if (JS_HAS_EQUALS(a)) {
-      return UNINTERCEPTED(a == null);
-    }
-  }
- return false;
-}
-
-eqNullB(var a) {
-  if (JS('bool', @'# == null', a)) return true;
-  if (JS('bool', @'typeof # === "object"', a)) {
-    if (JS_HAS_EQUALS(a)) {
-      return UNINTERCEPTED(a == null) === true;
-    }
-  }
- return false;
-}
-
 gt$slow(var a, var b) {
   if (checkNumbers(a, b)) {
     return JS('bool', @'# > #', a, b);