[roll] Roll fuchsia [superproject] Roll llvm-project/libc e9be5ed..1b1fc39 (4 commits)

1b1fc39 [libc][support][FixedVector] add reverse iterator (#86732)
c5ea0bc [libc] s/NULL/nullptr (#86867)
29f7dca [libc] Disable testing for NVPTX debug builds (#86856)
217a4ea [libc] Move baremetal write_to_stderr implementation to io.cpp (#86890)

GitOrigin-RevId: a4e33c829fdffccbb9f8b0124d0abe8295dc6f35
Roller-URL: https://ci.chromium.org/b/8752192363626951361
CQ-Do-Not-Cancel-Tryjobs: true
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1016981
Original-Revision: 4c19ab9c30dcaa1e50dd007eccfa2f16f5e5ba1a
Change-Id: I8bd33f585c6f1e6aa3c280fb3d78a0b58f2038e4
diff --git a/stem b/stem
index 8cf474d..90285e1 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="72068f6d5a9e62d36a094a63dd0dc12441a6c9eb"/>
+             revision="4c19ab9c30dcaa1e50dd007eccfa2f16f5e5ba1a"/>
   </projects>
   <hooks>
     <hook name="install-environment"