Support `void` as generic argument.

sdk/lib/_internal/js_runtime/lib/shared/embedded_names.dart

Index: sdk/lib/_internal/js_runtime/lib/shared/embedded_names.dart
diff --git a/sdk/lib/_internal/js_runtime/lib/shared/embedded_names.dart b/sdk/lib/_internal/js_runtime/lib/shared/embedded_names.dart
index 2fff7ec323c877f0e16e75c7acdd614db6fc6fd1..41fbc15b9ad6a650e0d7374fdd448b95fc00723e 100644
--- a/sdk/lib/_internal/js_runtime/lib/shared/embedded_names.dart
+++ b/sdk/lib/_internal/js_runtime/lib/shared/embedded_names.dart
@@ -327,10 +327,6 @@ enum JsGetName {
   /// Name used to tag a function type.
   FUNCTION_TYPE_TAG,
 
-  /// Name used to tag void return in function type representations in
-  /// JavaScript.
-  FUNCTION_TYPE_VOID_RETURN_TAG,
-
   /// Name used to tag return types in function type representations in
   /// JavaScript.
   FUNCTION_TYPE_RETURN_TYPE_TAG,
@@ -392,6 +388,11 @@ enum JsBuiltin {
   ///     JS_BUILTIN('=Object', JsBuiltin.createFunctionType)
   createFunctionTypeRti,
 
+  /// Returns whether the given rti is a void rti.
+  ///
+  ///     JS_BUILTIN("bool', JsBuiltin.isVoidRti, rti)
+  isVoidRti,
+
   /// Returns the JavaScript-constructor name given an rti encoding.
   ///
   ///     JS_BUILTIN('String', JsBuiltin.rawRtiToJsConstructorName, rti)