Refactored libgptf_fuzzer

The following are the updates to the fuzzer:
1. Randomized APIs & parameters
2. Added New APIs to the fuzzer
3. Improved Coverage of gpt.cc from 32% to 70%

Test: ./libgptf_fuzzer corpus/
Bug: 332255733
exec/s: 500

Change-Id: I5495f31a8e107e18a603d6c6ea92680107a26041
3 files changed