Bump LLVM submodule version to match upstream

This continues to move us beyond the advertised TF LLVM_COMMIT, which is not getting updated as frequently as I thought it should be.

Depends on https://github.com/google/iree/pull/736. Has to be a separate PR due to unfortunate repository syncing issues.

Closes https://github.com/google/iree/pull/737

PiperOrigin-RevId: 294464463

SUBMODULE_VERSIONS

diff --git a/SUBMODULE_VERSIONS b/SUBMODULE_VERSIONS
index 4ad727d..a3c9820 100644
--- a/SUBMODULE_VERSIONS
+++ b/SUBMODULE_VERSIONS
@@ -6,7 +6,7 @@
 48233ad3d45b314a83474b3704ae09638e3e2621 third_party/glslang
 495ced98de99a5895e484b2e09771edb42d3c7ab third_party/google_tracing_framework
 f2fb48c3b3d79a75a88a99fba6576b25d42ec528 third_party/googletest
-835c81923efee0cef1c64b25a34cf0872fa1e634 third_party/llvm-project
+52086f802e37fbb2acc61c49120990b0b3fd10cd third_party/llvm-project
 80d452484c5409444b0ec19383faa84bb7a4d351 third_party/pybind11
 b73f111094da3e380a1774b56b15f16c90ae8e23 third_party/sdl2
 b252a50953ac4375cb1864e94f4b0234db9d215d third_party/spirv_headers

third_party/llvm-project

diff --git a/third_party/llvm-project b/third_party/llvm-project
index 835c819..52086f8 160000
--- a/third_party/llvm-project
+++ b/third_party/llvm-project
@@ -1 +1 @@
-Subproject commit 835c81923efee0cef1c64b25a34cf0872fa1e634
+Subproject commit 52086f802e37fbb2acc61c49120990b0b3fd10cd