build: Remove legacy fuzzing code The previous fuzzing code was static and required each target to be defined within oss-fuzz.sh. In addition, the Makefile target fuzz would statically call each one of the targets.
The changes remove the no longer needed oss-fuzz.sh. Please refer to the linked
upstream for more information.
The Makefile target is mostly for convenience when smoke testing all Go native
fuzzing are working. The changes now enumerate all packages which contains at
least one fuzzing test, and then execute them for the period set in FUZZ_TIME.
Signed-off-by: Paulo Gomes <pjbgf@linux.com>