net: don't run IP stack required tests on IP stack unimplemented kernels

Fixes #10787.

Change-Id: I35c96808a713dafb1f0fea301fa3f3528fe6a5bf
Reviewed-on: https://go-review.googlesource.com/9948Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

src/net/main_test.go

@@ -97,7 +97,7 @@ func printLeakedGoroutines() {
 	if len(gss) == 0 {
 		return
 	}
-	fmt.Fprintf(os.Stderr, "Leaked goroutines:\n")
+	fmt.Fprintf(os.Stderr, "Running goroutines:\n")
 	for _, gs := range gss {
 		fmt.Fprintf(os.Stderr, "%v\n", gs)
 	}
@@ -130,7 +130,7 @@ func printLeakedSockets() {
 	if len(sos) == 0 {
 		return
 	}
-	fmt.Fprintf(os.Stderr, "Leaked sockets:\n")
+	fmt.Fprintf(os.Stderr, "Inflight sockets:\n")
 	for s, so := range sos {
 		fmt.Fprintf(os.Stderr, "%v: %v\n", s, so)
 	}

src/net/platform_test.go

@@ -14,7 +14,8 @@ import (
 // testableNetwork reports whether network is testable on the current
 // platform configuration.
 func testableNetwork(network string) bool {
-	switch ss := strings.Split(network, ":"); ss[0] {
+	ss := strings.Split(network, ":")
+	switch ss[0] {
 	case "ip+nopriv":
 		switch runtime.GOOS {
 		case "nacl":
@@ -46,6 +47,16 @@ func testableNetwork(network string) bool {
 			return false
 		}
 	}
+	switch ss[0] {
+	case "tcp4", "udp4", "ip4":
+		if !supportsIPv4 {
+			return false
+		}
+	case "tcp6", "udp6", "ip6":
+		if !supportsIPv6 {
+			return false
+		}
+	}
 	return true
 }