[8] 2019-10-31, Bulk backports to sh/jdk8

[Aleksey Shipilev]

https://cr.openjdk.java.net/~shade/shenandoah/backports/jdk8u-20191031/webrev.01/

Another batch of sh/jdk8 backports for early testing:

 [backport] 8225441: Cleanup ShenandoahHeap::atomic_compare_exchange_oop
 [backport] 8232729: Shenandoah: assert ShenandoahHeap::cas_oop addresses are aligned
 [backport] 8225514: Shenandoah: ShenandoahCodeRoots should inherit from AllStatic
 [backport] 8225357: Rewire ShenandoahHeap::maybe_update_with_forwarded for contending fixups
 [backport] 8232102: Shenandoah: print everything in proper units
 [backport] 8229416: Shenandoah: Demote or remove ShenandoahOptimize*Final optimizations
 [backport] 8229419: Shenandoah: Cleanup LRB strength selector code

Testing: {x86_32, x86_64} x {fastdebug,release} hotspot_gc_shenandoah

-- 
Thanks,
-Aleksey