Add fuzz tests for binder RecordedTransaction

This change adds tests for reading RecordedTransaction from a fuzzed
file, and for creating a RecordedTransaction from fuzzed Parcels and
other fields. Both tests will also excercise writing an instantiated
RecordedTransaction to a file.

This change also includes fixes for two issues uncovered by
binder_recordedTransactionFileFuzz:

- Guard RecordedTransaction from reading past file end
- Fix leak from failing to unmmap files when loading a
RecordedTransaction.

Test: Run the added fuzzers: binder_recordedTransactionFileFuzz and
binder_recordedTransactionFuzz

Change-Id: I7cc443d0915f9cea8289c5a4abbcb1ad323a0ed8