Remove duplicate test

spec/controllers/projects/pipelines_controller_spec.rb

@@ -62,42 +62,6 @@ describe Projects::PipelinesController do
       end
     end
 
-    context 'when using legacy stages', :request_store do
-      it 'returns JSON with serialized pipelines' do
-        get_pipelines_index_json
-
-        expect(response).to have_gitlab_http_status(:ok)
-        expect(response).to match_response_schema('pipeline')
-
-        expect(json_response).to include('pipelines')
-        expect(json_response['pipelines'].count).to eq 6
-        expect(json_response['count']['all']).to eq '6'
-        expect(json_response['count']['running']).to eq '2'
-        expect(json_response['count']['pending']).to eq '1'
-        expect(json_response['count']['finished']).to eq '3'
-
-        json_response.dig('pipelines', 0, 'details', 'stages').tap do |stages|
-          expect(stages.count).to eq 3
-        end
-      end
-
-      it 'does not execute N+1 queries' do
-        get_pipelines_index_json
-
-        control_count = ActiveRecord::QueryRecorder.new do
-          get_pipelines_index_json
-        end.count
-
-        create_all_pipeline_types
-
-        # There appears to be one extra query for Pipelines#has_warnings? for some reason
-        expect { get_pipelines_index_json }.not_to exceed_query_limit(control_count + 1)
-
-        expect(response).to have_gitlab_http_status(:ok)
-        expect(json_response['pipelines'].count).to eq 12
-      end
-    end
-
     it 'does not include coverage data for the pipelines' do
       get_pipelines_index_json