RFR: BACKOUT - Remove the generations array

[Jesper Wilhelmsson]

Hi,

The change to remove the generations array caused non-trivial test failures in 
the nightly testing that is unlikely to be fixed before the next round of 
nightly testing starts. According to the new gatekeeper policy this means that 
the change should be backed out.

Webrev for backout:
http://cr.openjdk.java.net/~jwilhelm/8061805/webrev.00/

Original webrev:
http://cr.openjdk.java.net/~jwilhelm/8055702/webrev.01/

Bug:
https://bugs.openjdk.java.net/browse/JDK-8061805

Since the webrev is automatically generated by "hg backout" I will review it 
myself and will therefore only require one additional reviewer.

Thanks!
/Jesper