Update prebuilt Clang to r510928 (18.0.0). am: 878f994050

Original change: https://android-review.googlesource.com/c/platform/prebuilts/clang/host/darwin-x86/+/2871685

Change-Id: Ia1e4b8e7b51ea8c4c8e5e1cc92eade11f626acd9
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>