Merge "Update LLVM toolchain README" into tm-dev am: 3e473165be

Original change: https://googleplex-android-review.googlesource.com/c/platform/prebuilts/clang/host/linux-x86/+/18142597

Change-Id: Id778a4fdf5a053271420d9c4c0df47c2656ca1cb
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>