test: common: Actually use different AF_UNIX sockets for newTempAddress

Previously, we were reusing SocketTestBase.socketFile(), which may
result in unexpected errors due to race conditions.

Create new AF_UNIX temp addresses using
AFUNIXSocketAddress.ofNewTempFile() instead.

junixsocket-common/src/test/java/org/newsclub/net/unix/domain/AFUNIXAddressSpecifics.java

@@ -48,7 +48,7 @@ private AFUNIXAddressSpecifics() {
 
   @Override
   public AFSocketAddress newTempAddress() throws IOException {
-    return AFUNIXSocketAddress.of(SocketTestBase.socketFile());
+    return AFUNIXSocketAddress.ofNewTempFile();
   }
 
   @Override