RFR: 8150758: [TESTBUG] need jvmti tests for module aware agents

[Dmitry Dmitriev]

Hello,

Please review new tests for module aware agents. There are 3 tests:
1) MAAClassFileLoadHook.java - verifies ClassFileLoadHook event with 
different combinations of can_generate_early_vmstart and 
can_generate_early_class_hook_events JVMTI capabilities. Expects to 
find(or not) class from java.base module in the right VM phase.
2) MAAClassLoadPrepare.java - verifies ClassLoad and ClassPrepare events 
with and without can_generate_early_vmstart JVMTI capability. Expects to 
find(or not) class from java.base module in the VM start phase.
3) MAAThreadStart.java - verifies ThreadStart event with 
can_generate_early_vmstart JVMTI capability. Expect to find events in 
the VM start phase.

JBS: https://bugs.openjdk.java.net/browse/JDK-8150758
webrev.00: http://cr.openjdk.java.net/~ddmitriev/8150758/webrev.00/ 
<http://cr.openjdk.java.net/%7Eddmitriev/8150758/webrev.00/>
Testing: RBT on all platforms

Thanks,
Dmitry