Update prebuilt Clang to r383902b. am: e25ca94f0c am: 4314724279

Original change: https://googleplex-android-review.googlesource.com/c/platform/prebuilts/clang/host/darwin-x86/+/11834657

Change-Id: I6da2117abad9770f73a21ec3b7d2183bfef5321c