patch sync/atomic; typepatch fix (don't change types)

cl/_testlibgo/atomic/in.go

@@ -5,6 +5,20 @@ import (
 )
 
 func main() {
-	var v int64 = 100
-	println(atomic.AddInt64(&v, 1))
+	var v int64
+
+	atomic.StoreInt64(&v, 100)
+	println("store:", atomic.LoadInt64(&v))
+
+	ret := atomic.AddInt64(&v, 1)
+	println("ret:", ret, "v:", v)
+
+	swp := atomic.CompareAndSwapInt64(&v, 100, 102)
+	println("swp:", swp, "v:", v)
+
+	swp = atomic.CompareAndSwapInt64(&v, 101, 102)
+	println("swp:", swp, "v:", v)
+
+	ret = atomic.AddInt64(&v, -1)
+	println("ret:", ret, "v:", v)
 }