test: get out of the endless while loop, when bind failed

When bind() fails in this test, then /tmp get filled up with
temp files and upcoming tests will fail, because they need to create
temp files, too. Better exit from the loop.
Test still needs to be investigated to fix the failing bind().

Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

test/nptl/tst-cancel4.c

@@ -1015,6 +1015,8 @@ tf_accept (void *arg)
       if (++tries > 10)
 	{
 	  printf ("%s: too many unsuccessful bind calls\n", __FUNCTION__);
+	  /* prevent endless loop, when bind fails forever */
+	  exit (1);
 	}
 
       strcpy (sun.sun_path, "/tmp/tst-cancel4-socket-1-XXXXXX");