Tests

Improve cli help somewhat, creating an Experimental group #19272

Job	Run time
Type check our own code (py39-ubuntu)	1m 39s
Test suite with py311-ubuntu	9m 4s
Test suite with py310-ubuntu	12m 23s
Type check our own code (py39-windows-64)	2m 29s
Test suite with py39-ubuntu, mypyc-compiled	16m 54s
Test suite with py314-windows-64	27m 18s
mypyc runtime tests with py310-ubuntu	4m 44s
Formatting and code style with Black + ruff	2m 1s
Test suite with py312-ubuntu, mypyc-compiled	14m 39s
Test mypyc suite with 32-bit Python	8m 56s
Test suite with py313-ubuntu, mypyc-compiled	14m 1s
Test suite with py314-ubuntu, mypyc-compiled	14m 19s
mypyc runtime tests with py313-macos	4m 48s
	2h 13m 15s

Provide feedback