bpo-28129: fix ctypes crashes (#386) (#3800)

* init commit, with initial tests for from_param and fields __set__ and __get__, and some additions to from_buffer and from_buffer_copy

* added the rest of tests and patches. probably only a first draft.

* removed trailing spaces

* replace ctype with ctypes in error messages

* change back from ctypes instance to ctype instance

(cherry picked from commit 1bea762d9ec823544c530d567330a47f64d93d4f)
7 files changed