Revert "Fix updating packages map on reload and add a regression test"

runtime/observatory/lib/src/service/object.dart

Index: runtime/observatory/lib/src/service/object.dart
diff --git a/runtime/observatory/lib/src/service/object.dart b/runtime/observatory/lib/src/service/object.dart
index 815bd8f24d2c4f8c19fa0d072ab6afbc418fcfd8..8b8c332a220217dfd787468b7655ddf27b362612 100644
--- a/runtime/observatory/lib/src/service/object.dart
+++ b/runtime/observatory/lib/src/service/object.dart
@@ -1356,15 +1356,11 @@ class Isolate extends ServiceObjectOwner implements M.Isolate {
     return invokeRpc('getSourceReport', params);
   }
 
-  Future<ServiceMap> reloadSources(
-      {String rootLibUri, String packagesUri, bool pause}) {
+  Future<ServiceMap> reloadSources({String rootLibUri, bool pause}) {
     Map<String, dynamic> params = <String, dynamic>{};
     if (rootLibUri != null) {
       params['rootLibUri'] = rootLibUri;
     }
-    if (packagesUri != null) {
-      params['packagesUri'] = packagesUri;
-    }
     if (pause != null) {
       params['pause'] = pause;
     }