patch fun after how get origin fun

not use UnPatch
``` go
package main

import (
"fmt"
sm "github.com/cch123/supermonkey"
"time"
)
//go:noinline
func Now() time.Time {
return time.Time{}
}

func main() {
sm.Patch(time.Now, Now)
fmt.Println(time.Now())
// how call origin Now fun
}
```