feat: provide a custom variable for typeCheckingMode #116

Job	Run time
test (ubuntu-latest, 27.2, false)	47s
test (ubuntu-latest, 28.2, false)	49s
test (ubuntu-latest, 29.4, false)	56s
test (macos-latest, 28.2, false)	1m 54s
test (macos-latest, 29.4, false)	2m 13s
test (windows-latest, 27.2, false)	1m 32s
test (windows-latest, 28.2, false)	1m 11s
test (windows-latest, 29.4, false)	1m 21s
test (ubuntu-latest, snapshot, true)	43s
test (macos-latest, snapshot, true)	1m 23s
test (windows-latest, snapshot, true)	5m 32s
	18m 21s

Provide feedback