* tool/ruby_vm/models/bare_instructions.rb (predefine_attributes):
`sp_inc` attribute which may return negative values must be
signed `rb_snum_t`, to be signed-expanded at type promotion.
* vm_insnhelper.h (ADJ_SP): removed the workaround for platforms
where rb_num_t is wider than int.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62103 b2dd03c8-39d4-4d8f-98ff-823fe69b080e