Add Module#const_set specs for frozen module
Fix Module#const_set for frozen module
Add Module#autoload specs for frozen module
Fix {Kernel,Module}.#autoload for frozen module
Module#freeze should freeze `constant_table` as `method_table`
Merge pull request #2582 from kachick/set_constant_on_frozen_module

Module#const_set and {Kernel,Module}.#autoload should raise exceptions on frozen module