net: remove unixgram test sockets

Backport https://golang.org/cl/163277 from the master library.

Updates https://gcc.gnu.org/PR89406

Change-Id: I42cea70a7334af725461b2c5b4967a3f1903fa94
Reviewed-on: https://go-review.googlesource.com/c/163200
Reviewed-by: Than McIntosh <thanm@google.com>
diff --git a/libgo/go/net/listen_test.go b/libgo/go/net/listen_test.go
index 6c3f70c..6c9b92a 100644
--- a/libgo/go/net/listen_test.go
+++ b/libgo/go/net/listen_test.go
@@ -780,6 +780,9 @@
 				continue
 			}
 			c.Close()
+			if network == "unixgram" {
+				os.Remove(address)
+			}
 		}
 	})
 }
diff --git a/libgo/go/net/mockserver_test.go b/libgo/go/net/mockserver_test.go
index 5302935..e085f44 100644
--- a/libgo/go/net/mockserver_test.go
+++ b/libgo/go/net/mockserver_test.go
@@ -17,8 +17,6 @@
 )
 
 // testUnixAddr uses ioutil.TempFile to get a name that is unique.
-// It also uses /tmp directory in case it is prohibited to create UNIX
-// sockets in TMPDIR.
 func testUnixAddr() string {
 	f, err := ioutil.TempFile("", "go-nettest")
 	if err != nil {
diff --git a/libgo/go/net/splice_test.go b/libgo/go/net/splice_test.go
index 26e3ac4..324103e 100644
--- a/libgo/go/net/splice_test.go
+++ b/libgo/go/net/splice_test.go
@@ -242,6 +242,7 @@
 	if err != nil {
 		t.Fatal(err)
 	}
+	defer os.Remove(addr.Name)
 	up, err := ListenUnixgram("unixgram", addr)
 	if err != nil {
 		t.Fatal(err)