RFR (S): JDK-8055816: Remove dead code in g1BlockOffsetTable

[Bengt Rutisson]

Hi all,

Can I get reviews for this small change to remove dead code from the 
G1BlockOffsetTable implementation?

Webrev:
http://cr.openjdk.java.net/~brutisso/8055816/webrev.00/

Bug report:
https://bugs.openjdk.java.net/browse/JDK-8055816


Background:
I'm working on a fix for JDK-8025564 that will involve adding 
verification code to G1BlockOffsetTable. There is already some 
verification code in that class but most of it is unused. To be able to 
know what code I need to add I first need to remove the dead code that 
is not being used.

This patch removes all the dead code that I found. Mostly it is just 
simple removal of unused methods. There is one change that is a little 
bit more complicated. The G1BlockOffsetArray constructor took a 
parameter called init_to_zero. Some places in the code checked for this 
value, but in reality it was always true. The checks were for 
!init_to_zero, so the corresponding code was also dead code.

Thanks,
Bengt