Revert "Extract interceptor calls from raw is-checks."

sdk/lib/_internal/compiler/implementation/js_backend/backend.dart

Index: sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart b/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
index 6bf39b4bc3d3749b1b4c4b0a2856ee5263d9368e..7a809b704837a6196034428490b1419483c962a2 100644
--- a/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
+++ b/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
@@ -1284,23 +1284,6 @@ class JavaScriptBackend extends Backend {
     }
   }
 
-  /**
-   * Returns [:true:] if the checking of [type] is performed directly on the
-   * object and not on an interceptor.
-   */
-  bool hasDirectCheckFor(DartType type) {
-    Element element = type.element;
-    return element == compiler.stringClass ||
-        element == compiler.boolClass ||
-        element == compiler.numClass ||
-        element == compiler.intClass ||
-        element == compiler.doubleClass ||
-        element == jsArrayClass ||
-        element == jsMutableArrayClass ||
-        element == jsExtendableArrayClass ||
-        element == jsFixedArrayClass;
-  }
-
   Element getExceptionUnwrapper() {
     return compiler.findHelper(const SourceString('unwrapException'));
   }