replace non-blocking send, receive syntax with select

R=golang-dev, nigeltao, niemeyer, r
CC=golang-dev
https://golang.org/cl/4079053
diff --git a/test/chan/perm.go b/test/chan/perm.go
index d08c035..c725829 100644
--- a/test/chan/perm.go
+++ b/test/chan/perm.go
@@ -9,49 +9,46 @@
 var (
 	cr <-chan int
 	cs chan<- int
-	c chan int
+	c  chan int
 )
 
 func main() {
-	cr = c		// ok
-	cs = c		// ok
-	c = cr		// ERROR "illegal types|incompatible|cannot"
-	c = cs		// ERROR "illegal types|incompatible|cannot"
-	cr = cs	// ERROR "illegal types|incompatible|cannot"
-	cs = cr	// ERROR "illegal types|incompatible|cannot"
+	cr = c  // ok
+	cs = c  // ok
+	c = cr  // ERROR "illegal types|incompatible|cannot"
+	c = cs  // ERROR "illegal types|incompatible|cannot"
+	cr = cs // ERROR "illegal types|incompatible|cannot"
+	cs = cr // ERROR "illegal types|incompatible|cannot"
 
-	c <- 0		// ok
-	ok := c <- 0	// ok
-	_ = ok
-	<-c		// ok
-	x, ok := <-c	// ok
-	_, _ = x, ok
+	c <- 0 // ok
+	<-c    // ok
+	//TODO(rsc): uncomment when this syntax is valid for receive+check closed
+	//	x, ok := <-c	// ok
+	//	_, _ = x, ok
 
-	cr <- 0	// ERROR "send"
-	ok = cr <- 0	// ERROR "send"
-	_ = ok
-	<-cr		// ok
-	x, ok = <-cr	// ok
-	_, _ = x, ok
+	cr <- 0 // ERROR "send"
+	<-cr    // ok
+	//TODO(rsc): uncomment when this syntax is valid for receive+check closed
+	//	x, ok = <-cr	// ok
+	//	_, _ = x, ok
 
-	cs <- 0	// ok
-	ok = cs <- 0	// ok
-	_ = ok
-	<-cs		// ERROR "receive"
-	x, ok = <-cs	// ERROR "receive"
-	_, _ = x, ok
+	cs <- 0 // ok
+	<-cs    // ERROR "receive"
+	////TODO(rsc): uncomment when this syntax is valid for receive+check closed
+	////	x, ok = <-cs	// ERROR "receive"
+	////	_, _ = x, ok
 
 	select {
-	case c <- 0:	// ok
-	case x := <-c:	// ok
+	case c <- 0: // ok
+	case x := <-c: // ok
 		_ = x
 
-	case cr <- 0:	// ERROR "send"
-	case x := <-cr:	// ok
+	case cr <- 0: // ERROR "send"
+	case x := <-cr: // ok
 		_ = x
 
-	case cs <- 0:	// ok
-	case x := <-cs:	// ERROR "receive"
+	case cs <- 0: // ok
+	case x := <-cs: // ERROR "receive"
 		_ = x
 	}
 }