* proc.c (rb_method_entry_min_max_arity): fix missing break in switch.
  This was introduced in r38236, which is not intentional apparently.
  This has caused no actual harm because VM_METHOD_TYPE_OPTIMIZED is
  not used except for OPTIMIZED_METHOD_TYPE_SEND, but may do in
  future.  Coverity Scan found this inadequacy.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40926 b2dd03c8-39d4-4d8f-98ff-823fe69b080e