Update TEST_MAPPING am: f38775c3c7

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/ryu/+/2411576

Change-Id: I81a1974688dd063ca1150cbf77db76729999e3d7
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>