Jigsaw Enhancement RFR: 8159145 Add JVMTI function GetModuleByPackageName

[serguei.spitsyn at oracle.com]

Please, review the Jigsaw fix for the enhancement:
   https://bugs.openjdk.java.net/browse/JDK-8159145


The Hotspot webrev:
http://javaweb.sfbay.sun.com/java/svc/ss45998/webrevs/2016/hotspot/8159145-jigsaw-jvmti-pkg.1/

The Jdk webrev:
http://javaweb.sfbay.sun.com/java/svc/ss45998/webrevs/2016/hotspot/8159145-jigsaw-jvmti-pkg.jdk1/


Summary:

JVM TI agents that instrument code in named modules need the Module at 
class load time.

   One way to do this is by introducing a new ClassFileLoadHook that 
takes an additional parameter but this approach is disruptive.
   The alternative option is a JVM TI function that maps a classloader + 
package name to a module.
   We were initially not confident with this approach so we introduced 
it as JVM function JVM_GetModuleByPackageName.
   Based on experience to date then this approach seems okay and so this 
function needs to be promoted to a JVMTI function.

   This fix is to introduce new JVMTI function GetModuleByPackageName.
   It includes new jtreg test with native JVMTI agent.

   A CCC is fast-tracked and getting an approval is in progress.

Testing:
    Run newly developed jtreg test.

Thanks,
Serguei