fuzz: specify protocol with fuzz target name

fuzz: specify protocol with fuzz target name

cf https://redmine.openinfosecfoundation.org/issues/4125

This allows fuzz_applayerparser_parse to fuzz one specific
app-layer protocol based on the binary name, as is done
with the environment variable FUZZ_APPLAYER
That is if we rename/copy to fuzz_applayerparser_parse_smb,
it will fuzz only SMB protocol
This way, we can easily produce different fuzz targets for
each protocol in oss-fuzz

(cherry picked from commit e9b76a0e663ce5c2f8900f90a4f4fd7ed3436335)