Change iface_fuzzer input flags.

There are 4 input parameters to iface_fuzzer:
vts_spec_dir: directory on the target containing .vts spec.
vts_exec_size: # of function calls per LLVMFuzzerTestOneInput.
vts_target_iface: name of interface targeted for fuzz, e.g. "INfc".
vts_service_name: service name of target interface, e.g. "default".

vts_ prefix may seem a bit out of place;
we use to avoid possible name collision with libFuzzer flags.

Test: manual
Change-Id: I29a1ad5791a653f7d75b43b867533375c1d4ebd8
3 files changed