Enable clang to version 9.0. am: acad6360b1 am: 3c954f07fd am: c91e2ccf02 am: 1533644c17 am: f2dfeb3baa

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/clang-sys/+/1350712

Change-Id: I582f37de4803f4f9910610c17fa1d7a2a3f95f6a