[8u] 2020-07-21, Bulk backports to sh/jdk8

[Roman Kennke]

Yep, looks good! Thanks!

Roman

On Tue, 2020-07-21 at 10:20 +0200, Aleksey Shipilev wrote:
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> https://cr.openjdk.java.net/~shade/shenandoah/backports/jdk8u-20200721/webrev.01/
> 
> This backports a few changes to 8u, mostly test improvements:
>  [backport] 8242375: Shenandoah: Remove
> ShenandoahHeuristic::record_gc_start/end methods
>  [backport] 8247860: Shenandoah: add update watermark line in rich
> assert failure message
>  [backport] 8247751: Shenandoah: options tests should run with
> smaller heaps
>  [backport] 8247754: Shenandoah: mxbeans tests can be shorter
>  [backport] 8247757: Shenandoah: split heavy tests by heuristics to
> improve parallelism
> 
> Testing: hotspot_gc_shenandoah {fastdebug,release}
>