[mypyc] Implement new-style builtins.len for all supported type

[TH3CHARLie]

This PR completes the support of the new style builtins.len for dict, set, tuple and generic cases.

[JukkaL]

Looks good! It's nice to see all the various IR features being used here.

[TH3CHARLie]

@JukkaL I saw your comment in #9290. There is one thing suspicious that originally the return type for dict, set and tuple are int:

func_op(name='builtins.len',
        arg_types=[dict_rprimitive],
        result_type=int_rprimitive,
        error_kind=ERR_NEVER,
        emit=emit_len)

With this PR, this code snippet makes them short_int:

            return self.binary_int_op(short_int_rprimitive, size_value, offset,
                                      BinaryIntOp.LEFT_SHIFT, line)

Could this be a possible cause? However, please note that len for list was originally of short_int return type.

[JukkaL]

@TH3CHARLie I narrowed the issue down to mypyc/mypyc#756.

[TH3CHARLie]

@TH3CHARLie I narrowed the issue down to mypyc/mypyc#756.

cool! I just checked the issue, though I haven't come up any quick fix yet.

[JukkaL]

cool! I just checked the issue, though I haven't come up any quick fix yet.

I can also help with this, since I'd like to get fix out soon.