* internal.h: move common string/hash flags to include file.
* ext/objspace/objspace_dump.c: remove flags shared above.
* hash.c: ditto.
* string.c: ditto.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43647 b2dd03c8-39d4-4d8f-98ff-823fe69b080e