cmd/go: fix "go run" cgo source when cgo is disabled

also move a cgo-depend test to appropriate source file in runtime.

R=golang-dev, dave, adg, rsc
CC=golang-dev
https://golang.org/cl/7393063

src/pkg/runtime/crash_test.go

@@ -99,14 +99,6 @@ func TestLockedDeadlock2(t *testing.T) {
 	testDeadlock(t, lockedDeadlockSource2)
 }
 
-func TestCgoSignalDeadlock(t *testing.T) {
-	got := executeTest(t, cgoSignalDeadlockSource, nil)
-	want := "OK\n"
-	if got != want {
-		t.Fatalf("expected %q, but got %q", want, got)
-	}
-}
-
 const crashSource = `
 package main
 
@@ -191,68 +183,3 @@ func main() {
 	select {}
 }
 `
-
-const cgoSignalDeadlockSource = `
-package main
-
-import "C"
-
-import (
-	"fmt"
-	"runtime"
-	"time"
-)
-
-func main() {
-	runtime.GOMAXPROCS(100)
-	ping := make(chan bool)
-	go func() {
-		for i := 0; ; i++ {
-			runtime.Gosched()
-			select {
-			case done := <-ping:
-				if done {
-					ping <- true
-					return
-				}
-				ping <- true
-			default:
-			}
-			func() {
-				defer func() {
-					recover()
-				}()
-				var s *string
-				*s = ""
-			}()
-		}
-	}()
-	time.Sleep(time.Millisecond)
-	for i := 0; i < 64; i++ {
-		go func() {
-			runtime.LockOSThread()
-			select {}
-		}()
-		go func() {
-			runtime.LockOSThread()
-			select {}
-		}()
-		time.Sleep(time.Millisecond)
-		ping <- false
-		select {
-		case <-ping:
-		case <-time.After(time.Second):
-			fmt.Printf("HANG\n")
-			return
-		}
-	}
-	ping <- true
-	select {
-	case <-ping:
-	case <-time.After(time.Second):
-		fmt.Printf("HANG\n")
-		return
-	}
-	fmt.Printf("OK\n")
-}
-`