fix(math): remove redundant allocations in MinInt and MaxInt

Author: Radovenchyk

math/int.go

@@ -406,12 +406,12 @@ func (i Int) Abs() Int {
 
 // MinInt return the minimum of the ints
 func MinInt(i1, i2 Int) Int {
-	return Int{min(i1.BigInt(), i2.BigInt())}
+	return Int{min(i1.i, i2.i)}
 }
 
 // MaxInt returns the maximum between two integers.
 func MaxInt(i, i2 Int) Int {
-	return Int{max(i.BigInt(), i2.BigInt())}
+	return Int{max(i.i, i2.i)}
 }
 
 // String returns human-readable string