RFR:8139368:-javaagent and -Dcom.sun.management need to add to the initial set of modules to resolve

[Alexander Kulyakhtin]

Hi,

Could you, please, review this test-only change (adding a new test).

CR: https://bugs.openjdk.java.net/browse/JDK-8139368 "-javaagent and -Dcom.sun.management need to add to the initial set of modules to resolve"
Webrev: http://cr.openjdk.java.net/~akulyakh/8139368_01/

The new tests starts java with the -javaagent option at the same time limiting the initial modules not to include the java.instrument module.
The test then verifies that java starts successfully and that both the agent and the application produce the expected output.

The other part of the CR, related to the -Dcom.sun.management, is not addressed by this fix as it is being addressed by a separate CR JDK-8131061 

Best regards,
Alexander