[fuzzer] Add a fuzzer for frame info functions

Add a fuzzer that fuzzes all helper functions that take compressed
input. This fuzzer caught one out of bounds read in
`ZSTD_decompressBound()`.

tests/fuzz/fuzz.py

@@ -36,6 +36,7 @@ TARGETS = [
     'block_decompress',
     'dictionary_round_trip',
     'dictionary_decompress',
+    'zstd_frame_info',
 ]
 ALL_TARGETS = TARGETS + ['all']
 FUZZ_RNG_SEED_SIZE = 4