cmd/api: break the builds

There is some question about whether the api tool is
running on Windows (see issue 6124), and now I'm
starting to question whether it runs on any of the builders,
since both darwin/amd64 and linux/amd64 are crashing for me
in the api tool due to a recent cgo-related change, and yet
the dashboard is happy.

If the dashboard is still happy after this CL, we have a problem.

Update #6124

TBR=golang-dev
CC=golang-dev
https://golang.org/cl/13632053

src/cmd/api/goapi.go

@@ -110,6 +110,8 @@ func setContexts() {
 func main() {
 	flag.Parse()
 
+	panic("yes, the api checks are really running")
+
 	if !strings.Contains(runtime.Version(), "weekly") && !strings.Contains(runtime.Version(), "devel") {
 		if *nextFile != "" {
 			fmt.Printf("Go version is %q, ignoring -next %s\n", runtime.Version(), *nextFile)