Update TEST_MAPPING am: 0c46775b9d

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/num-bigint/+/2399598

Change-Id: I76cd215938b025a85e2ea639a1e39e12b3a85736
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>