On my machine, gdb reverse-next does not work with memcpy and memset.
Add naive implementation of those functions to override.

And arena-overflow error as well.  They should not be caught by
`rescue` by default.

This reverts commit eb5a606f and
079f310f.
The rescue stack works differently from ensure stack, so the change
caused #3686 and #3688. It might take long to solve the problems,
so that I would revert the changes for now. Fix #3688

This reverts commit 31e30686.

This issue is related to #3640.

It generates a wasted empty array for each `super` call though.
It should be fixed in the future, if possible.

We know this is not perfect, but this change makes hack like #3679
bit harder. Harmless for useful cases.