test_websocket_client.c: Disable websocket_client_create_and_connect test.

This test was occasionally failing, with:

  WARNING[5812]: http.c:1939 httpd_helper_thread: Failed to set
      TCP_NODELAY on HTTP connection: Bad file descriptor
  ERROR[5812]: iostream.c:91 ast_iostream_nonblock: Failed to get
      fcntl() flags for file descriptor: Bad file descriptor
  ERROR[5812]: iostream.c:569 ast_iostream_close: close() failed: Bad
      file descriptor

Disabled for now by making the test explicit only.

Change-Id: I778f6cbb6104c6b4e89737a2eaf1a9540888d351