[11] Bulk backports to sh/jdk11

[Roman Kennke]

Hi Aleksey,

> https://cr.openjdk.java.net/~shade/shenandoah/backports/jdk11-20200206/webrev.01/
> 
> This batch backports these simple fixes:
>  [backport] 8237570: Shenandoah: cleanup uses of allocation/free threshold in static heuristics
>  [backport] 8237586: Shenandoah: provide option to disable periodic GC
>  [backport] 8238153: CTW: C2 (Shenandoah) compilation fails with "Unknown node in get_load_addr:
> CreateEx"
>  [backport] 8237038: Shenandoah: Reduce thread pool size in TestEvilSyncBug.java test
>  [backport] 8233850: Shenandoah: Shenandoah thread count ergonomics should be container aware
>  [backport] 8236851: Shenandoah: More details in Traversal GC event messages
> 
> All apply cleanly.
> 
> Testing: hotspot_gc_shenandoah {fastdebug, release}

Looks good! Thank you!

Roman