Merge "Add missed TEST_MAPPINGs" am: 8a2f224db3 am: 251a34db9c

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/grpcio-sys/+/1924517

Change-Id: Ic2500768f66cc7acd5dd800b84e5dbda595915be