* Added `FIELDPATH` to the list of available fuzzing targets.
* Added fuzzing method for creating `FIRFieldPath` objects.
* Added corpus and dictionary for `FIRFieldPath`.
* Added fuzzing targets read from env variable.
* Refactored Serializer fuzz tests in a separate file
* Separate header file for each fuzzing target.
* Write crashing outputs using `artifact_prefix` flag to `NSTemporaryDirectory`.