[roll] Roll fuchsia [build] Fix two issues in ifs_shared_library_libs()

The `.as-needed` target was missing the dependency necessary to
ensure the real link stub ELF file was actually generated before
the generated linker script that refers to it goes into a link.

The ldscript metadata fragments using a path to the link stub
that's relative to root_build_dir did not work with GNU gold,
which does not look relative to the current working directory
after looking in a script-relative directory like LLD
does.  (Both linkers then go on to look at the -L / GN lib_dirs
search path.)  Instead, all ifs_shared_library_libs() targets now
generate the files containing those fragments in a single shared
directory, so every fragment can use a path relative to its link
stub that's relative to that one shared directory.

Cq-Include-Trybots: luci.turquoise.global.try:run-postsubmit-tryjobs
Run-All-Tests: true
Original-Bug: 342469121
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1061132
Original-Revision: 53c980becf9790bb83374c9110edc45aee43192d
GitOrigin-RevId: 0911dbf050afc5bf3875ac58f7a6c5cd5b9b4c7f
Change-Id: Ic435495865b209d83a0dd9255ed605abda65928d
diff --git a/stem b/stem
index c53e19d..1b8302e 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="2b395060ae249203764e315e25e3cb9d535ffd2b"/>
+             revision="53c980becf9790bb83374c9110edc45aee43192d"/>
   </projects>
   <hooks>
     <hook name="install-environment"