[roll] Roll llvm-project/libc [libc][math] Refactor exp2 implementation to header-only in src/__support/math folder. (#161297)

Part of #147386

in preparation for: https://discourse.llvm.org/t/rfc-make-clang-builtin-math-functions-constexpr-with-llvm-libc-to-support-c-23-constexpr-math-functions/86450

GitOrigin-RevId: 3e78c313bcfa54f8d1f1bdf221611d461e56111c
Original-Revision: b6f04bd2244b0c0e711e2d203f857a11a2badee3

Rolled-Repo: https://llvm.googlesource.com/llvm-project/libc
Rolled-Commits: 8a55b3b9df92f2..b6f04bd2244b0c
Roller-URL: https://cr-buildbucket.appspot.com/build/8701882568772024769
CQ-Do-Not-Cancel-Tryjobs: true
Cq-Include-Trybots: luci.turquoise.global.try:run-postsubmit-tryjobs
Change-Id: I3f85377825bbd49f3b991112f07a8ec855f321ed
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1384067
Commit-Queue: GI Roller <global-integration-roller@fuchsia-infra.iam.gserviceaccount.com>
diff --git a/manifests/third_party/all b/manifests/third_party/all
index 26c94bf..72715c2 100644
--- a/manifests/third_party/all
+++ b/manifests/third_party/all
@@ -295,7 +295,7 @@
     <project name="llvm-project/libc"
              path="third_party/llvm-libc/src"
              remote="https://llvm.googlesource.com/llvm-project/libc"
-             revision="8a55b3b9df92f24390374141fe401e8adb7c5c44"/>
+             revision="b6f04bd2244b0c0e711e2d203f857a11a2badee3"/>
     <project name="third_party/luci-go"
              path="third_party/luci-go"
              revision="fd977bf9e01d199a529f28af6dc10fe0fa35d9e7"
diff --git a/third_party/llvm-libc/src b/third_party/llvm-libc/src
index 8a55b3b..b6f04bd 160000
--- a/third_party/llvm-libc/src
+++ b/third_party/llvm-libc/src
@@ -1 +1 @@
-Subproject commit 8a55b3b9df92f24390374141fe401e8adb7c5c44
+Subproject commit b6f04bd2244b0c0e711e2d203f857a11a2badee3