[bazel] Fix serialization when not doing summary

Before this CL, if using the incremental compiler in bazels
kernel_worker, did not do summaries and did ask to "exclude-non-sources"
one would still get the entire thing (including loaded summaries etc)
(i.e. it would behave as if "exclude-non-sources" wasn't set).

This CL fixes it and makes it serialize as in the non-incremental case.

Change-Id: I396b53664a3d1ac32a243e903c8ff5c049fca453
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/113021
Commit-Queue: Jake Macdonald <jakemac@google.com>
Reviewed-by: Jake Macdonald <jakemac@google.com>

utils/bazel/kernel_worker.dart

@@ -321,7 +321,11 @@ Future<ComputeKernelResult> computeKernel(List<String> args,
             includeSources: false, includeOffsets: false));
       }
 
-      return Future.value(fe.serializeComponent(incrementalComponent));
+      return Future.value(fe.serializeComponent(incrementalComponent,
+          filter: excludeNonSources
+              ? (library) => sources.contains(library.importUri)
+              : null,
+          includeOffsets: true));
     });
   } else if (summaryOnly) {
     kernel = await fe.compileSummary(state, sources, onDiagnostic,