Remove Python 2 compatibility SON methods #8212

Job	Run time
Typing Tests (3.11)	52s
Typing Tests (3.9)	1m 1s
Test async's minimum dependencies and Python	49s
Make an sdist	13s
DocTest	1m 11s
CPython 3.9-ubuntu-latest	11m 23s
Link Check	6m 34s
Test using minimum dependencies and supported Python	44s
static	3m 9s
CPython pypy-3.10-ubuntu-latest	12m 19s
Docs Checks	46s
CPython 3.13t-ubuntu-latest	11m 50s
Install from SDist and Test	53s
	51m 44s

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