RFR: 8057632 - Remove auxiliary code used to handle the generations array

[Jesper Wilhelmsson]

Hi,

This is the next part of the generation array removal. I have split this change 
into several parts to ease the review. These webrevs build on top of each other.


1. Removing prev_gen(), next_gen(), and get_gen(int)
Webrev: http://cr.openjdk.java.net/~jwilhelm/8057632/remove_get_gen/


2. Move the genspecs from GenCollectedHeap to GenCollectorPolicy
Webrev: http://cr.openjdk.java.net/~jwilhelm/8057632/move_genspecs/


3. Remove n_gen()
Webrev: http://cr.openjdk.java.net/~jwilhelm/8057632/remove_n_gen/


4. Remove the levels concept.
Webrev: http://cr.openjdk.java.net/~jwilhelm/8057632/remove_levels/


5. Random cleanups made throughout this work
Webrev: http://cr.openjdk.java.net/~jwilhelm/8057632/cleanup/



If you prefer to look at all changes at once, this is a webrev with all these 
changes: http://cr.openjdk.java.net/~jwilhelm/8057632/webrev/

The bug I have filed for this work is:
https://bugs.openjdk.java.net/browse/JDK-8057632

I will probably file more RFEs and push these different parts one by one.

Thanks,
/Jesper