Tests

Fix slots issue with deferred base #20093

Job	Run time
Test mypyc suite with 32-bit Python	9m 41s
Type check our own code (py310-ubuntu)	1m 44s
Test suite with py314t-ubuntu, mypyc-compiled	17m 48s
Test suite with py314-ubuntu, mypyc-compiled	14m 52s
Parallel tests with py314-ubuntu, mypyc-compiled	27m 40s
Test suite with py313-ubuntu, mypyc-compiled	15m 30s
mypyc runtime tests with py310-ubuntu	5m 44s
Test suite with py312-ubuntu	10m 8s
Parallel tests with py314-ubuntu, interpreted	24m 29s
Type check our own code (py310-windows-64)	2m 17s
Test suite with py310-ubuntu, mypyc-compiled	15m 34s
Test suite with py311-ubuntu	9m 28s
Formatting and code style with Black + ruff	2m 1s
mypyc runtime tests with py313-macos	5m 21s
Test suite with py314-windows-64	28m 1s
	3h 10m 18s

Provide feedback