Use faster way to get AnalysisContext in execution domain notifications.

pkg/analysis_server/lib/src/domain_execution.dart

Index: pkg/analysis_server/lib/src/domain_execution.dart
diff --git a/pkg/analysis_server/lib/src/domain_execution.dart b/pkg/analysis_server/lib/src/domain_execution.dart
index 08ff54e41f22a592e918d4d53510d70683519f7e..59d70afbfc23f474508e4d3749fc84364f7cf863 100644
--- a/pkg/analysis_server/lib/src/domain_execution.dart
+++ b/pkg/analysis_server/lib/src/domain_execution.dart
@@ -154,10 +154,7 @@ class ExecutionDomainHandler implements RequestHandler {
     ServerPerformanceStatistics.executionNotifications.makeCurrentWhile(() {
       Source source = notice.source;
       String filePath = source.fullName;
-      if (!_isInAnalysisRoot(filePath)) {
-        return;
-      }
-      AnalysisContext context = server.getAnalysisContext(filePath);
+      AnalysisContext context = server.getContainingContext(filePath);
       if (context == null) {
         return;
       }