test/jdk/java/net/NetworkInterface/NetworkInterfaceRetrievalTests.java should open the java.net package

test/jdk/java/net/NetworkInterface/NetworkInterfaceRetrievalTests.java has been modified recently (see JDK-8225239), and now performs deep reflection ( setAccessible(true) ) on a non-public member, java.net.NetworkInterface::isBoundInetAddress. As such, the test should be run in othervm mode, and `open` the `java.net` to the unnamed module ( where the test lives ).

The following illegal access warning message is generated by JTReg as a result of the deep reflection:

WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by NetworkInterfaceRetrievalTests to method java.net.NetworkInterface.isBoundInetAddress(java.net.InetAddress)
WARNING: Please consider reporting this to the maintainers of NetworkInterfaceRetrievalTests
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release