number protocol issues #4682

• table design. function pointer vs table offset Improve: binary ops with Number Protocol #4615 (comment)
• unary ops handling. Improve: binary ops with Number Protocol #4615 (comment)
• test_collections regression related to slot selection https://github.com/RustPython/RustPython/pull/4615/files#diff-a2a882635e20e8e9439f090d33513502a7af648286efebfa4e4bc37270c44784R264
• heaptype concerns Improve: binary ops with Number Protocol #4615 (comment)
• __builtins__.pow is still not using number protocol
• Remove #[pymethod] from number types' binary ops
• Remove PyNumber assumption from PyNumberMethods

cc @xiaozhiyan @qingshi163
part of #3244