RFR JDK-8151913: Fix module dependencies in java/net tests

[John Jiang]

Hi,
Please review the fix for explicitly declaring module dependencies for 
java net tests.

Issue: https://bugs.openjdk.java.net/browse/JDK-8151913
Webrev: http://cr.openjdk.java.net/~jjiang/8151913/webrev.00

Best regards,
John Jiang