misc/ios: simplify breakpoint timeout

The clever partial timer I added interacts badly with iOS app launch
timeout termination. A fixed timeout will be easier to debug.

Change-Id: I6eb4ee5f1431539f00fa707e8cde6f3cf86983fc
Reviewed-on: https://go-review.googlesource.com/8083Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

misc/ios/go_darwin_arm_exec.go

@@ -150,10 +150,8 @@ func run(bin string, args []string) (err error) {
 	// Manage the -test.timeout here, outside of the test. There is a lot
 	// of moving parts in an iOS test harness (notably lldb) that can
 	// swallow useful stdio or cause its own ruckus.
-	brTimeout := 5 * time.Second
 	var timedout chan struct{}
 	if t := parseTimeout(args); t > 1*time.Second {
-		brTimeout = t / 4
 		timedout = make(chan struct{})
 		time.AfterFunc(t-1*time.Second, func() {
 			close(timedout)
@@ -209,7 +207,7 @@ func run(bin string, args []string) (err error) {
 	fmt.Fprintln(lldb, `run`)
 	// Sometimes we don't see "reason = breakpoint", so we time out
 	// and try to continue.
-	if err := waitFor("br getwd", "stop reason = breakpoint", brTimeout); err != nil {
+	if err := waitFor("br getwd", "stop reason = breakpoint", 10*time.Second); err != nil {
 		return err
 	}
 	if err := waitFor("br getwd prompt", "(lldb)", 0); err != nil {