* ext/objspace/objspace_dump.c (dump_append): avoid fflush.

	  because dump_append_string_value() iterates over each chars,
	  fflush()-ing here effectively issues system calls on every single
	  bytes exist in a ruby process.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46959 b2dd03c8-39d4-4d8f-98ff-823fe69b080e