[roll] Roll fuchsia [fxfs] Extend test_writes_fail_fsverity_enabled

There were a few checks that were missing to ensure that verity-enabled
files cannot be changed in any way.  Extend the existing tests to check
these.  The code already handles these cases, this is just for
additional testing.

Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1190072
Original-Revision: a90b745cc8a8ecc6d00e20014be43473eb70ec53
GitOrigin-RevId: 7a22d19fec2824134233e2b07d83b8869c30b68b
Change-Id: Iacaa4ea82e3cc732615a2882f1d260087c67d0dc
diff --git a/stem b/stem
index 1b2c1c7..d86a4d2 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="1e640429cd20a783354759fac74633d8929e317c"/>
+             revision="a90b745cc8a8ecc6d00e20014be43473eb70ec53"/>
   </projects>
   <hooks>
     <hook name="install-environment"