chore: revert "feat(gnovm): implement overflow checking at VM level (#…

…3250)"

This reverts commit 68aff64.

This PR was merged before discussions were complete. It was finally
rejected because it does not comply with Go specification, which
stipulates that overflow on signed integers do not trigger runtime
panic. See https://go.dev/ref/spec#Integer_overflow

examples/gno.land/p/demo/grc/grc20/token.gno

@@ -1,6 +1,7 @@
 package grc20
 
 import (
+	"math/overflow"
 	"std"
 	"strconv"
 
@@ -169,24 +170,17 @@ func (led *PrivateLedger) Approve(owner, spender std.Address, amount uint64) err
 }
 
 // Mint increases the total supply of the token and adds the specified amount to the specified address.
-func (led *PrivateLedger) Mint(address std.Address, amount uint64) (err error) {
+func (led *PrivateLedger) Mint(address std.Address, amount uint64) error {
 	if !address.IsValid() {
 		return ErrInvalidAddress
 	}
 
-	defer func() {
-		if r := recover(); r != nil {
-			if r != "addition overflow" {
-				panic(r)
-			}
-			err = ErrOverflow
-		}
-	}()
-
-	// Convert amount and totalSupply to signed integers to enable
-	// overflow checking (not occuring on unsigned) when computing the sum.
-	// The maximum value for totalSupply is therefore 1<<63.
-	sum := int64(led.totalSupply) + int64(amount)
+	// XXX: math/overflow is not supporting uint64.
+	// This checks prevents overflow but makes the totalSupply limited to a uint63.
+	sum, ok := overflow.Add64(int64(led.totalSupply), int64(amount))
+	if !ok {
+		return ErrOverflow
+	}
 
 	led.totalSupply = uint64(sum)
 	currentBalance := led.balanceOf(address)