Update LLVM used in x86 CI dist builds to 15.0.0

Author: Kobzol

src/ci/docker/host-x86_64/dist-x86_64-linux/build-clang.sh

@@ -4,7 +4,7 @@ set -ex
 
 source shared.sh
 
-LLVM=llvmorg-14.0.5
+LLVM=llvmorg-15.0.0
 
 mkdir llvm-project
 cd llvm-project