merge revision(s) 39932,39934,39935,39937,39955,40491:
Use assert_separately to speed up on test-all This creates large string and it pressure GC.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@40542 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merge revision(s) 39932,39934,39935,39937,39955,40491:
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@40542 b2dd03c8-39d4-4d8f-98ff-823fe69b080e