dart2js: patch file support cleanup

sdk/lib/_internal/js_runtime/lib/annotations.dart

Index: sdk/lib/_internal/js_runtime/lib/annotations.dart
diff --git a/sdk/lib/_internal/js_runtime/lib/annotations.dart b/sdk/lib/_internal/js_runtime/lib/annotations.dart
index 2862612259d1786e6bb043c929aaa1184dad7d28..483dd0c6a95b34563a9f859017baf65adb3691d1 100644
--- a/sdk/lib/_internal/js_runtime/lib/annotations.dart
+++ b/sdk/lib/_internal/js_runtime/lib/annotations.dart
@@ -43,19 +43,8 @@ class Native {
 }
 
 class _Patch {
-  final String version;
-
-  const _Patch(this.version);
+  const _Patch();
 }
 
 /// Annotation that marks the declaration as a patch.
-const _Patch patch = const _Patch(null);
-
-/// Annotation that marks the declaration as a patch for the full emitter.
-const _Patch patch_full = const _Patch('full');
-
-/// Annotation that marks the declaration as a patch for the lazy emitter.
-const _Patch patch_lazy = const _Patch('lazy');
-
-/// Annotation that marks the declaration as a patch for the startup emitter.
-const _Patch patch_startup = const _Patch('startup');
+const _Patch patch = const _Patch();