Refactoring of tp_clear#1460

Merged

lostmsu merged 2 commits intopythonnet:masterfrom

losttech:PR/Clear

May 23, 2021

Commits on May 23, 2021

refactored tp_clear in ExtensionType and descendants into a virtual C# function Clear
lostmsu
committed
all Dealloc overrides simply duplicate Clear, so just call both from tp_dealloc and don't override Dealloc
lostmsu
committed