RFR: JDK-8058118: Generate modules.list during the build

[Erik Joelsson]

Hello,

The checked in modules.list file defines the dependencies between 
modules for the build. The dependency information in this file is 
already captured in the modules.xml. Rather than keeping two copies of 
this information, with this change, modules.list is generated during the 
build.

Chris provided the java implementation for the actual list generation. 
I've made the makefile changes.

Bug: https://bugs.openjdk.java.net/browse/JDK-8058118
Webrevs: http://cr.openjdk.java.net/~erikj/8058118/

/Erik