Share srcs in rust_defaults. am: ad1f4a661c am: 7b308b39c9 am: 0b14238bc3 am: f33af3e878

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/rustc-hash/+/1366081

Change-Id: Ia4ae3f2a0bb7b8af623d5a0d1bf71b7f22a67a85