os: stop manually setting sticky bit on file creation on *BSD, Solaris

// This program demonstrates the new sticky‑bit handling on *BSD and Solaris.
// It attempts to create a file with the sticky bit set. On systems that
// support the sticky bit, the file is created successfully. On systems
// that do not, an error is returned. The GODEBUG flag can be set to
// restore the old behavior, but it is not used here.

package main

import (
	"fmt"
	"os"
)

func main() {
	// Attempt to create a file with the sticky bit.
	f, err := os.OpenFile("sticky_test.txt", os.O_CREATE|os.O_RDWR, os.FileMode(0o644|os.ModeSticky))
	if err != nil {
		fmt.Printf("Error creating file with sticky bit: %v\n", err)
		return
	}
	defer f.Close()
	fmt.Println("File created successfully with sticky bit set (if supported).")
}