Import source for the fxhash crate am: 4bcb072d30 am: 7c28bc31a5

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/fxhash/+/2163440

Change-Id: Id85b47abd5a55d12ccb8808158d8f4d02fc45e65
Signed-off-by: Automerger Merge Worker <[email protected]>