dart2js: Inline Primitives.identicalImplementation into identical patch.

sdk/lib/_internal/js_runtime/lib/js_helper.dart

Index: sdk/lib/_internal/js_runtime/lib/js_helper.dart
diff --git a/sdk/lib/_internal/js_runtime/lib/js_helper.dart b/sdk/lib/_internal/js_runtime/lib/js_helper.dart
index fd53e61d99b7ad7c47fd318e0d17b1e6c233ea5e..4898f2acb8df85463fdcaba6b959e5086435cd7e 100644
--- a/sdk/lib/_internal/js_runtime/lib/js_helper.dart
+++ b/sdk/lib/_internal/js_runtime/lib/js_helper.dart
@@ -1482,12 +1482,6 @@ class Primitives {
     return JS('', '#.apply(#, #)', jsFunction, function, positionalArguments);
   }
 
-  static bool identicalImplementation(a, b) {
-    return JS('bool', '# == null', a)
-      ? JS('bool', '# == null', b)
-      : JS('bool', '# === #', a, b);
-  }
-
   static StackTrace extractStackTrace(Error error) {
     return getTraceFromException(JS('', r'#.$thrownJsError', error));
   }