[roll] Roll fuchsia [ddk-firmware-test] Use DriverTestRealm

This test can't use DriverTestRealm directly, as it wants to mock
out /boot/ and /system (which is not supported). But it can
still use the underlying components of DTR and route them
in different ways.

Original-Bug: 86318
Original-Bug: 85745
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/599423
Original-Revision: 86d6aa586e470c2f39395d3ac68087749d776e9e
GitOrigin-RevId: ed59a21a25014832c6bf78f02eae9f9e8197046d
Change-Id: I47b6f3e92eada75bab22862adba906dd06f41290
diff --git a/stem b/stem
index 6298f77..431dd8f 100644
--- a/stem
+++ b/stem
@@ -10,7 +10,7 @@
              githooks=""
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="adba538719b6f30ae56f0bb1db22ab3e4102c01a"/>
+             revision="86d6aa586e470c2f39395d3ac68087749d776e9e"/>
   </projects>
   <hooks>
     <hook name="install-environment"