RFR (M): 8184346: Clean up G1CMBitmap

[Thomas Schatzl]

Hi again,

  a few more cleanups could be found that were worth picking up here.

On Thu, 2017-07-20 at 13:06 +0200, Thomas Schatzl wrote:
> Hi all,
> 
>   Erik and Mikael had a look at it and suggested several further
> cleanups, removing about 40 LOC more. These included:
> 
> - instead of G1CMBitMapR0 use properly const'ified G1CMBitmaps
> - change the _start and _word_size members into an equivalent
> MemRegion
> - minor cleanups, removing obsolete asserts, simplify code.
> 
> Webrevs:
> http://cr.openjdk.java.net/~tschatzl/8184346/webrev.1_to_2/ (diff)
> http://cr.openjdk.java.net/~tschatzl/8184346/webrev.2/ (full)
> Testing:
> jprt

Webrevs:
http://cr.openjdk.java.net/~tschatzl/8184346/webrev.2_to_3/ (diff)
http://cr.openjdk.java.net/~tschatzl/8184346/webrev.3/ (full)
Testing:
jprt

Thanks,
  Thomas