tests

Optionally disable c bindings #192

Job	Run time
kzg_ci	39s
backend_ci (ubuntu-latest, blst)	14m 26s
backend_ci (ubuntu-latest, zkcrypto)	51s
backend_ci (ubuntu-latest, arkworks)	19m 48s
backend_ci (ubuntu-latest, arkworks3)	5m 16s
backend_ci (ubuntu-latest, constantine)	24m 56s
backend_ci (windows-latest, blst)	4m 29s
backend_ci (windows-latest, zkcrypto)	8m 20s
backend_ci (windows-latest, arkworks)	6m 12s
backend_ci (windows-latest, arkworks3)	5m 33s
backend_ci (windows-latest, constantine)	7m 36s
backend_ci (macos-latest, blst)	6m 12s
backend_ci (macos-latest, zkcrypto)	8m 34s
backend_ci (macos-latest, arkworks)	6m 28s
backend_ci (macos-latest, arkworks3)	8m 18s
backend_ci (macos-latest, constantine)	9m 49s
	2h 17m 27s

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