test_gc.rb: read binary
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49510 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
test_gc.rb: read binary
binary encoding to get rid of invalid byte sequence exception.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49510 b2dd03c8-39d4-4d8f-98ff-823fe69b080e