Bulk backports to sh/jdk8

[Roman Kennke]

>> Changesets:
>> http://cr.openjdk.java.net/~rkennke/backport-shjdk8-2020-04-23/changesets.txt
>>
>> Full webrev:
>> http://cr.openjdk.java.net/~rkennke/backport-shjdk8-2020-04-23/webrev.00/
>>
>> Testing: hotspot_gc_shenandoah (x86, aarch64)
> 
> *) Please grep for leftover ShenandoahKeepAliveBarrier in source code? 8u might have some surprises
> there, for example in x86_32 parts;

No, nothing.

> *) Indent is a bit off in shenandoahConcurrentMark.cpp here:
> 
>  220   ShenandoahSATBBufferClosure* _satb_cl;
>  221   OopClosure*            const _cl;
>  222   MarkingCodeBlobClosure*              _code_cl;

Right. Fixed.

> *) Not related to this backport. But looking at for example TestClassLoaderLeak.java, it looks to me
> IU can use the same bundle of heuristics like normal mode uses. Probably something to fix in
> upstream and let it trickle?
> 
>  125         String[][][] modeHeuristics = new String[][][] {
>  126              {{"normal"},  {"adaptive", "compact", "static", "aggressive"}},
>  127              {{"iu"},      {"adaptive", "aggressive"}},
>  128              {{"passive"}, {"passive"}}

Yeah, let's do that separately.

> *) In new tests, does it not complain about vm.gc.Shenandoah and vm.graal.enabled flags? IIRC, not
> all test flags are available in 8u, and that's why test backports remove those lines...

Right. Also, needed to fix the @library tags.

http://cr.openjdk.java.net/~rkennke/backport-shjdk8-2020-04-23/webrev.01/

Good now?

Roman