[roll] Roll fuchsia [diagnostics-kcounter] Delete diagnostics-kcounter core_shard

All the actual code was already deleted, but this had to be soft
migrated out of core.

Original-Fixed: b/326315218
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1037892
Original-Revision: 25c0e3fde4a8e62f5f9a2982c55c3d8322c3ee5f
GitOrigin-RevId: 61da3e9e5c2384e200480c3e941262b7e34d1dd1
Change-Id: I7cd6a2ebb02c60b7e694a29249e012728756cdc1
diff --git a/stem b/stem
index 113e352..18258d3 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="7a3132c4788e396c0fe789ef41671a82dea38cc3"/>
+             revision="25c0e3fde4a8e62f5f9a2982c55c3d8322c3ee5f"/>
   </projects>
   <hooks>
     <hook name="install-environment"