[roll] Roll fuchsia [fxfs] Add golden file tests for serialized types

Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1416114
Original-Revision: d21cd956ec1c652053e03d5956b9b58a8f0e6610
GitOrigin-RevId: beca1d298ff3aa0ba6a5c0628a5bea33b25368d7
Change-Id: I48f6bf5c99b1356dee304e1e4a407e24e92029df

stem

diff --git a/stem b/stem
index 8e01010..da8f4a2 100644
--- a/stem
+++ b/stem
@@ -7,7 +7,7 @@
             manifest="manifests/platform"
             root=""
             remote="https://fuchsia.googlesource.com/fuchsia"
-            revision="ae7149fabc46b227a270c35d0c4f48cfa213c38d"/>
+            revision="d21cd956ec1c652053e03d5956b9b58a8f0e6610"/>
   </imports>
   <projects>
     <project name="cobalt"