binder_ndk: sanitize binder descriptor for logging

Invalid char in a string causes "implicit-conversion" ubsan error.
So, when printing "read" binder descriptor for log, sanitize it by
replacing invalid char with '?'.

Bug: n/a
Test: binder_parcel_fuzzer
Change-Id: I51f806ff28ccc52f9b3da328ace4ca8c348483ba