build-llvm: Bump to LLVM 16.0.2

A couple relevant changes since 16.0.0:
- Fix compilation for ARM (failures in generating SEH unwind info)
  for very specific cases
- Link the ASAN DLL before other libs and objects, to make sure it gets
  initialized as early as possible
- Allow double backslashes in the PATH in ASAN
- Allow llvm-rc to look for a clang executable named "clang-16", if the
  other alternatives aren't available
- Improve the performance of buffered raw_ostream within LLVM

build-llvm.sh

@@ -16,7 +16,7 @@
 
 set -e
 
-: ${LLVM_VERSION:=llvmorg-16.0.0}
+: ${LLVM_VERSION:=llvmorg-16.0.2}
 ASSERTS=OFF
 unset HOST
 BUILDDIR="build"