Test analyzers against Zeek test suite

[bbannier]

Since some analyzers in this plugin explicitly replace builtin Zeek analyzers, we should consider testing them against the respective Zeek test suites to ensure users don't see regressions when installing this plugin.

[rsmmr]

This would be nice to do, but isn't trivial as some differences are expected, so one needs to dig in track things down. FWIW, the current HTTP and DNS analyzers are derived from earliers versions for the old Spicy prototype where I did this, so conceptually they should be producing the expected results, but of course we could have introduced problems with the new implementation.