Kani

Add harnesses for safety of primitive conversions #1194

Job	Run time
Kani List	10m 3s
Verify std library (partition 1)	26m 30s
Verify std library (partition 2)	36m 44s
Verify std library (partition 3)	31m 42s
Verify std library (partition 4)	40m 27s
Verify std library (partition 1)	21m 41s
Verify std library (partition 2)	31m 14s
Verify std library (partition 3)	30m 23s
Verify std library (partition 4)	34m 28s
	4h 23m 12s

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