merge revision(s) 51583,51594,51638: [Backport #11444]
* io.c (rb_io_each_codepoint): read more data when read partially. [ruby-core:70379] [Bug #11444] * io.c (rb_io_each_codepoint): raise an exception at incomplete character before EOF when conversion takes place. [Bug #11444]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@52831 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merge revision(s) 51583,51594,51638: [Backport #11444]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@52831 b2dd03c8-39d4-4d8f-98ff-823fe69b080e