[Migrate] Remove two files that are already migrated

Change-Id: I60f83a66cbbeb1f71718f647a6133babb6398a4f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/402940
Auto-Submit: Brian Wilkerson <[email protected]>
Reviewed-by: Konstantin Shcheglov <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

Author: bwilkerson

pkg/analysis_server/analyzer_use_new_elements.txt

@@ -2,8 +2,6 @@ lib/plugin/protocol/protocol_dart.dart
 lib/src/analysis_server.dart
 lib/src/cider/rename.dart
 lib/src/handler/legacy/search_find_element_references.dart
-lib/src/lsp/handlers/handler_completion.dart
-lib/src/lsp/handlers/handler_completion_resolve.dart
 lib/src/lsp/handlers/handler_rename.dart
 lib/src/protocol_server.dart
 lib/src/services/correction/namespace.dart