Fix a sharing Dir.{glob,[]} spec
Fix a sharing Dir.open spec

This spec is sharing. But looks used only by Dir.open
Fix sharing IO#gets specs

This spec is sharing. But looks used only by IO#gets
Fix sharing Time.{new,now} specs

* Fix sharing
* Fix instance~class matcher
* Use `send` instead of `__send__` for adjusting style
Fix sharing Thread#{wakeup,run} and C-API(rb_thread_wakeup) specs
Fix sharing Struct#{each,each_pair,members,select,size,to_a} specs

This commit is a part of rubyspec/rubyspec#225.
Fix sharing String#{concat,<<} specs

This commit is a part of rubyspec/rubyspec#230.
Merge pull request #2539 from kachick/fix-sharing-specs

Fix some sharing specs