[roll] Roll fuchsia [fdf] Refactor driver index composite code

Move helper functions into a separate file. Add
test functions to make creating fake test data
easier.

Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1178033
Original-Revision: f9d86a012006675df39fffb381f9796725e8ab34
GitOrigin-RevId: 2ed9ebecb055997ab1189f5fca14e51109d70247
Change-Id: Ia86c8f2564c6d3a5191eec9530f62d5ee7b9e9cb

Author: Sarah Chan

stem

@@ -11,7 +11,7 @@
              githooks="integration/git-hooks"
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="ea41741f23b7a4ef89930a76675c838cfd72504d"/>
+             revision="f9d86a012006675df39fffb381f9796725e8ab34"/>
   </projects>
   <hooks>
     <hook name="install-environment"