* vm_core.h (VM_ENV_DATA_INDEX_ENV_PROC): ep[VM_ENV_DATA_INDEX_ENV_PROC] is
  allocated to mark a Proc which is created from iseq block.
  However, `lep[0]` keeps Proc object itself as a block handler (Proc).
  So we don't need to keep it.

* vm_core.h (VM_ENV_PROCVAL): ditto.

* vm.c (vm_make_env_each): do not need to keep blockprocval as special value.

* vm.c (vm_block_handler_escape): simply return Proc value.

* proc.c (proc_new):  we don't need to check Env because a Proc type block
  handler is a Proc object itself.
  [Bug #14782]

* test/ruby/test_proc.rb: add a test for [Bug #14782]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63494 b2dd03c8-39d4-4d8f-98ff-823fe69b080e