[roll] Roll fuchsia [ld] Emit symbolizer markup when LD_DEBUG is nonempty

This also fixes the missing build ID parsing for the main
executable in the POSIX case.

Original-Bug: 42080760
Cq-Include-Trybots: luci.turquoise.global.try:run-postsubmit-tryjobs
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/959292
Original-Revision: 69ab286d507c728b187d2104e6b6348913a2b978
GitOrigin-RevId: f52da46ff219358a591f665ec26233c5ce103fae
Change-Id: I39bfdb409ab6b919e724028dfe90c9b4f158d73d
diff --git a/stem b/stem
index ac27d25..6b6461b 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="8132a41eb4514c10479e221068901ee1b2684b01"/>
+             revision="69ab286d507c728b187d2104e6b6348913a2b978"/>
   </projects>
   <hooks>
     <hook name="install-environment"