Tests

Improve error message for incompatible **kwargs #22521

Job	Run time
Test mypyc suite with 32-bit Python	10m 54s
Test suite with py313-ubuntu, mypyc-compiled	16m 40s
Test suite with py312-ubuntu	9m 38s
Test suite with py314-ubuntu, mypyc-compiled	15m 51s
Test suite with py310-ubuntu, mypyc-compiled	17m 12s
Test suite with py315-ubuntu, mypyc-compiled	15m 13s
Test suite with py311-ubuntu	9m 43s
Test suite with py314-windows-64	31m 22s
mypyc runtime tests with py310-ubuntu	7m 4s
Type check our own code (py310-windows-64)	2m 0s
Parallel tests with py314-ubuntu, mypyc-compiled	29m 5s
Type check our own code (py310-ubuntu)	1m 14s
Parallel tests with py314-ubuntu, interpreted	26m 37s
Test suite with py314t-ubuntu, mypyc-compiled	17m 38s
mypyc runtime tests with py313-macos	5m 43s
Formatting and code style with Black + ruff	1m 48s
Parallel tests with py314-windows-64, interpreted	9m 42s
	3h 47m 24s

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