test_gem.rb: exclude default gems
* test/rubygems/test_gem.rb: check difference to exclude default
gems from the expected results. [Feature #13186]
Merge rubygems-2.6.11
This version fixed regression of rubygems-2.6.10.
https://github.com/rubygems/rubygems/pull/1856
See details of changelogs for 2.6.11 release:
https://github.com/rubygems/rubygems/blob/adfcf40502716080bd9cdfdd2e43bd4296872784/History.txt#L3
merge revision(s) 57523,57998: [Backport #13322]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_4@58001 b2dd03c8-39d4-4d8f-98ff-823fe69b080e