Change analysis server protocol to omit empty lists when optional.

pkg/analysis_server/lib/src/services/correction/fix_internal.dart

Index: pkg/analysis_server/lib/src/services/correction/fix_internal.dart
diff --git a/pkg/analysis_server/lib/src/services/correction/fix_internal.dart b/pkg/analysis_server/lib/src/services/correction/fix_internal.dart
index 59c8a209f12ff5521eb633bbfe8260b7e7b07985..4c10f1500d5f2e6533df4fa3f4f6ec3e8d62ece8 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix_internal.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix_internal.dart
@@ -206,7 +206,7 @@ class FixProcessor {
     if (fixFile == null) {
       fixFile = file;
     }
-    SourceFileEdit fileEdit = new SourceFileEdit(file, <SourceEdit>[]);
+    SourceFileEdit fileEdit = new SourceFileEdit(file);
     fileEdit.addAll(edits);
     // prepare Change
     String message = formatList(kind.message, args);