Remove no longer used arguments from the functions.

`a::B = c` should evaluate `a` then `c`. It used to be `c` then `a`. The
`OP_SETMCNST` instruction operands are designed for older order in mind.
Should we changed the operand order?

Fix tree of mruby-bin-example

But `mktime(3)` for the date returns `-1` which happen to be the
error value.

It was caused by #5628.

Toplevel includes the top of the method/class/module definitions.

Fixes file header in src/{cdump,dump}.c [ci skip]

The file headers were pointing to each other's files.

Fixing keyword arguments with `super`

Allows handling of unaligned cptrs for `MRB_NAN_BOXING`

This reverts commit d3b7601a.

It seems to be preferable to be able to handle pointers of type `char` as well.
For this purpose, `mrb_nanbox_tt_inline` has been reorganized.

- `MRB_NANBOX_TT_POINTER` has been split into `MRB_NANBOX_TT_OBJECT` and `MRB_NANBOX_TT_CPTR`
- `MRB_NANBOX_TT_SYMBOL` has been merged into `MRB_NANBOX_TT_MISC`

fix #5627

Improves presym scanning

Assert that `MRB_METHOD_CACHE_SIZE` is a power of 2

Assign after `mrb_irep_incref()` in `mrb_proc_new()`