[roll] Roll fuchsia [component][fuzzing] Mitigate integration test flake

This CL makes two changes to help reduce some of the flaking
RegistryIntegrationTests:

 * It explicitly shuts down the dispatcher in ConnectThenTimeout, to
   avoid the use-after-return caused by a pending FIDL response arriving
   during teardown.
 * It adds a `backtrace_request` to SyncWait that exceed the default
   threshold of 30 seconds. Hopefully this extra diagnostic information
   will reveal more about the cause of the rare, flaky hangs.

Original-Bug: 91050
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/634041
Original-Revision: 99cb503a45713a9c0df79acfc35e02fd62714514
GitOrigin-RevId: 5a4c5def76eceafe701079a6c7370e7830eef98d
Change-Id: Icad73d0e44c6afff9fab7ac7a2de6456c45902a6
diff --git a/stem b/stem
index 7ddee9f..623b914 100644
--- a/stem
+++ b/stem
@@ -10,7 +10,7 @@
              githooks=""
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="017e716e31c5bb4a21f66894eb035b42c4b0a3ec"/>
+             revision="99cb503a45713a9c0df79acfc35e02fd62714514"/>
   </projects>
   <hooks>
     <hook name="install-environment"