BigMin unit test now passes.

common/coords.go

@@ -252,8 +252,8 @@ func NaiveBigMin(minz, maxz, zcode int64) int64 {
 const (
 	bits = 12
 	msb  = uint8(3*bits - 1)
-	mask = int64(0x924924924924924)
-	full = int64(0xfffffffffffffff)
+	mask = int64(0x924924924)
+	full = int64(0xfffffffff)
 )
 
 func setbits(p uint8, v int64) int64 {