test_gc.rb: refine assertion
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44273 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
test_gc.rb: refine assertion
instead of bare assert.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44273 b2dd03c8-39d4-4d8f-98ff-823fe69b080e