Limit number of fds written in parcel

Certain input sequence causes fuzzers to pick a single fd from
getRandomFd and write it to parcel. Check object count before writing more fds and binders in parcel.

Test: m incidentd_service_fuzzer && adb sync data && adb shell
/data/fuzz/x86_64/incidentd_service_fuzzer/incidentd_service_fuzzer
-runs=1000
Test: atest fuzz_service_test
Test: atest binderRecordReplayTest
Bug: 296516864

Change-Id: I84359a7128fde359828c26ea43ac2559d1236708