Avoid creating deprecated resources in JavaAgent's constructor (#4400)
Avoid creating deprecated resources in JavaAgent's constructor (#4400)

### Problem

We are deprecating `resources` in JVM targets (d32b23acfcd92bae8596020f3de3b9fb490fbe5c). By using `assert_list` in `JavaAgent`'s constructor, an empty list of `resources` is always created and will trigger deprecation warning.

### Solution

Remove `assert_list`

### Result

`./pants test tests/python/pants_test/targets:java_agent`
landism/pants,twitter/pants,wisechengyi/pants,foursquare/pants,pombredanne/pants,15Dkatz/pants,foursquare/pants,wisechengyi/pants,wisechengyi/pants,landism/pants,15Dkatz/pants,landism/pants,benjyw/pants,landism/pants,pombredanne/pants,tdyas/pants,UnrememberMe/pants,pombredanne/pants,pantsbuild/pants,benjyw/pants,pombredanne/pants,foursquare/pants,benjyw/pants,pantsbuild/pants,15Dkatz/pants,15Dkatz/pants,tdyas/pants,15Dkatz/pants,foursquare/pants,twitter/pants,wisechengyi/pants,landism/pants,benjyw/pants,twitter/pants,foursquare/pants,twitter/pants,tdyas/pants,twitter/pants,pantsbuild/pants,15Dkatz/pants,wisechengyi/pants,tdyas/pants,landism/pants,fkorotkov/pants,15Dkatz/pants,foursquare/pants,UnrememberMe/pants,pantsbuild/pants,UnrememberMe/pants,baroquebobcat/pants,fkorotkov/pants,15Dkatz/pants,baroquebobcat/pants,tdyas/pants,jsirois/pants,foursquare/pants,benjyw/pants,foursquare/pants,twitter/pants,tdyas/pants,fkorotkov/pants,UnrememberMe/pants,wisechengyi/pants,wisechengyi/pants,UnrememberMe/pants,jsirois/pants,UnrememberMe/pants,landism/pants,fkorotkov/pants,wisechengyi/pants,UnrememberMe/pants,pombredanne/pants,UnrememberMe/pants,jsirois/pants,tdyas/pants,wisechengyi/pants,twitter/pants,twitter/pants,benjyw/pants,twitter/pants,pombredanne/pants,fkorotkov/pants,pantsbuild/pants,tdyas/pants,baroquebobcat/pants,baroquebobcat/pants,tdyas/pants,baroquebobcat/pants,UnrememberMe/pants,baroquebobcat/pants,landism/pants,pombredanne/pants,pantsbuild/pants,fkorotkov/pants,baroquebobcat/pants,foursquare/pants,fkorotkov/pants,pantsbuild/pants,fkorotkov/pants,baroquebobcat/pants,baroquebobcat/pants,benjyw/pants