RFR:8153978:New test to verify the modules info as returned by the JVMTI

[Alexander Kulyakhtin]

Hi, 

Could you, please, review these test-only changes (adding a new test).

CR: https://bugs.openjdk.java.net/browse/JDK-8153978 "New test to verify the modules info as returned by the JVMTI"
Webrev: http://cr.openjdk.java.net/~akulyakh/8153978_01/

The new test verifies that JVMTI returns the correct info about the modules loaded at the application startup. 
It also verifies that the returned info is consistent with the same info returned by the Java API.
It then loads a new named module and checks the correctness of the JVMTI info again.

Due to a tools issue https://bugs.openjdk.java.net/browse/CODETOOLS-7901662 the test can only be pushed in when the updated jtreg is released.
The test passes fine with the nightly jtreg build, containing the CODETOOLS-7901662 fix.

Best regards,
Alexander