Add initial fuzzing implementation
This MR adds fuzzing incl. regression tests of the test data generated by fuzzing. The MR contains no fuzz corpora so far as there are still memory leaks in asn1_array2tree().
More fuzzers will follow.
The MR also works with OSS-Fuzz - a commit for google/oss-fuzz is already prepared.
- Code modified for feature
- Test suite updated with functionality tests
- Test suite updated with negative tests
- Documentation updated
- There is a test suite reasonably covering new functionality or modifications
- Function naming, parameters, return values, types, etc., are consistent with other code
- This feature/change has adequate documentation added
- No obvious mistakes in the code