[roll] Roll fuchsia [fuchsia-async] Add host support for emulated Events

This CL adds basic support for Events to fuchsia-async's emulated
handles. The motivation for this is to enable all FIDL Rust GIDL tests
on host, where edit-build-test cycles are much faster.

Test: fx test fuchsia-async_test --host
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/777905
Original-Revision: f68258140f2c6c7c25d4aaffa9fe438f181c6583
GitOrigin-RevId: 82f34e2ac74154401a96c6ee5c6856dab36bcd5d
Change-Id: I8aeb7563863c427f7a84f731ad701ceee8f0abd8
diff --git a/stem b/stem
index b3b4e03..43fe067 100644
--- a/stem
+++ b/stem
@@ -11,7 +11,7 @@
              githooks="integration/git-hooks"
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="ee5921e959758627761f49b22580d12e0dff5188"/>
+             revision="f68258140f2c6c7c25d4aaffa9fe438f181c6583"/>
   </projects>
   <hooks>
     <hook name="install-environment"