[roll] Roll fuchsia [a11y] Fix stack-use-after-return in gesture tests

These tests had a stack-use-after-return caused by using raw
pointers to refer to stack-allocated MockContestMember inside data
structures that were passed to the recognizers which are allocated
within the test fixture.  Since the recognizer has ownership of
those data strcutures, we need to wait for it to be destroyed before
destroying MockContestMember.

Original-Fixed: 62984
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/502083
Original-Revision: 1d96e2317ce8c85911f4645165e797e0a9bbc648
GitOrigin-RevId: 605d0e6b6737d9d01d46f475d6e5b40f07296cae
Change-Id: I7ce220df203b91104a19dc108a1ce2621b47683d
diff --git a/stem b/stem
index e4dcc30..788a5ed 100644
--- a/stem
+++ b/stem
@@ -10,7 +10,7 @@
              githooks=""
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="17db22ad1ebd982845e0e893003c5e05f2e6989e"/>
+             revision="1d96e2317ce8c85911f4645165e797e0a9bbc648"/>
   </projects>
   <hooks>
     <hook name="install-environment"