RFR [10]: Revert G1 changes

[Roman Kennke]

Am 11.07.2017 um 11:30 schrieb Aleksey Shipilev:
> Hi,
>
> As discussed last week, we want to minimize our exposure in G1-specific code.
> This reverts G1 to mainline version in shenandoah-jdk10:
>    http://cr.openjdk.java.net/~shade/shenandoah/revert-g1-jdk10/webrev.01/
>
> Testing: hotspot_gc_shenandoah
>
> Thanks,
> -Aleksey
>
>
The change is good.

I am almost surprised that you don't get linker conflicts... different
definitions of CMBitMap, SATBMarkQueue, etc in two .cpp files?

Roman