Fix CTRL-Z handling

Fix #3802

This fixes `xterm -e fzf` hangs on CTRL-Z

* Replace SIGSTOP with SIGTSTP
* Do not rely on SIGCONT

src/terminal_windows.go

@@ -13,7 +13,3 @@ func notifyOnResize(resizeChan chan<- os.Signal) {
 func notifyStop(p *os.Process) {
 	// NOOP
 }
-
-func notifyOnCont(resizeChan chan<- os.Signal) {
-	// NOOP
-}