…thonGH-270)

(cherry picked from commit 365cb5b)

…thonGH-270)

(cherry picked from commit 365cb5b)

Stackless now uses an unmodified PyFrameObject structure. The field
PyFrameObject.f_executing now stores the information how to evaluate a
frame.

Additional consequences:
- all frame execution functions now take a "PyCFrameObject *" as first
  argument.
- Pickled frames no contain f_executing instead of the name of the
  execution function.

Consistent usage of SLP_FRAME_EXECUTING_VALUE

Cleanups and minor improvements. Fix _PyEval_EvalFrameDefault

Again minor improvements.

Stackless now uses an unmodified PyFrameObject structure. The field
PyFrameObject.f_executing now stores the information how to evaluate a
frame.

Additional consequences:
- all frame execution functions now take a "PyCFrameObject *" as first
  argument.
- Pickled frames no contain f_executing instead of the name of the
  execution function.

Remove unreachable code.

Fix test_sys.SizeofTest.test_objecttypes for frames. Stackless has now
again the same frame size as C-Python.

Integrate the C-function PyEval_EvalFrameEx_slp into into the C-function
slp_eval_frame_value and rename slp_eval_frame_value to
PyEval_EvalFrameEx_slp.

Adapt the gdb support library and document the change.

Back to PyEval_EvalFrameEx_slp and slp_eval_frame_value. But without
duplicated code.
Revert the gdb changes from the previous commit.

Eliminate duplicated code in ceval.c to improve maintainability.
Update changelog.txt.

* Use GH to signify Github handle of the user instead of "@".

"@" usually doesn't give any information about what exactly the handle means
since we don't know it is a Github handle from the commit message.

Changing the pattern to be `GH:` similar to what we do for Pull Requests
with (GH-).

Fixes #270

* Handle removing GH:-style Automerge-Triggered-By

...when automerge label is removed by a core-dev.

Co-authored-by: Abhilash Raj <raj.abhilash1@gmail.com>