RFR (M) 8140802 - Clean up and refactor of class loading code for CDS

[Ioi Lam]

Please review the following fix:

http://cr.openjdk.java.net/~iklam/8140802-cds-refactoring.v01/
Bug: Clean up and refactor of class loading code for CDS

    https://bugs.openjdk.java.net/browse/JDK-8140802

Summary of fix:

    We need to clean up and refactor the class loading code in order
    to support CDS in JDK9

    [1] Remove code that has been made obsolete by the module changes
        (such as supporting code used for meta-index file)
    [2] Add new whitebox API to be used by CDS-related tests.
    [3] Refactor the parsing of classlist files for future enhancements.
    [4] Add new APIs in the class loading code to support Oracle CDS 
enhancements.

Tests:

    JPRT
    RBT - with same set of tests as hs-rt nightly

Thanks
- Ioi