do not turn post-processing on for linux-cgo term

- fixes #15373
 - remove set OPOST output flag for termios
 - remove latent os.Exit call

Signed-off-by: Morgan Bauer <mbauer@us.ibm.com>

term/tc_linux_cgo.go

@@ -27,7 +27,6 @@ func MakeRaw(fd uintptr) (*State, error) {
 	newState := oldState.termios
 
 	C.cfmakeraw((*C.struct_termios)(unsafe.Pointer(&newState)))
-	newState.Oflag = newState.Oflag | C.OPOST
 	if err := tcset(fd, &newState); err != 0 {
 		return nil, err
 	}

term/term.go

@@ -127,6 +127,5 @@ func handleInterrupt(fd uintptr, state *State) {
 	go func() {
 		_ = <-sigchan
 		RestoreTerminal(fd, state)
-		os.Exit(0)
 	}()
 }