Fix lints: unnecessary_brace_in_string_interp

pkg/analysis_server/benchmark/perf/completion_timing_tests.dart

Index: pkg/analysis_server/benchmark/perf/completion_timing_tests.dart
diff --git a/pkg/analysis_server/benchmark/perf/completion_timing_tests.dart b/pkg/analysis_server/benchmark/perf/completion_timing_tests.dart
index f28ccf4e5e87e8087cf74ed7854ad107f9a3543a..a36a54a64b2ca492a0ee9d849f450f0c6bdace5f 100644
--- a/pkg/analysis_server/benchmark/perf/completion_timing_tests.dart
+++ b/pkg/analysis_server/benchmark/perf/completion_timing_tests.dart
@@ -78,7 +78,7 @@ class CompletionTimingTest extends AbstractTimingTest {
     await analysisFinished;
 
     print('analysis completed in ${stopwatch.elapsed}');
-    print('completion received at : ${timings}');
+    print('completion received at : $timings');
     await shutdown();
   }
 }