Merge "Refresh Android.bp, cargo2android.json, TEST_MAPPING." am: cded7e2bce am: 88a5c05d7e am: 99b119a02c am: 9af92ad78f

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/base64/+/1912045

Change-Id: Iface4a1ae2c24cef0fb8de3902afd451fe9a3bfe