RFR: 8273314: Add tier4 test groups [v3]

[Aleksey Shipilev]

On Mon, 6 Sep 2021 13:22:03 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> During the review of JDK-8272914 that added hotspot:tier{2,3} groups, @iignatev suggested to create tier4 groups that capture all tests not in tiers{1,2,3}. I have excluded `vmTestbase` and `hotspot:tier4,` because they take 10+ hours on my highly parallel machine. I have also excluded `applications` from `hotspot:tier4`, because they require test dependencies (e.g. jcstress).
>> 
>> Sample run:
>> 
>> 
>> ==============================
>> Test summary
>> ==============================
>>    TEST                                              TOTAL  PASS  FAIL ERROR   
>>>> jtreg:test/hotspot/jtreg:tier4                      426   425     1     0 <<
>>>> jtreg:test/jdk:tier4                               2891  2885     4     2 <<
>>    jtreg:test/langtools:tier4                            0     0     0     0   
>>    jtreg:test/jaxp:tier4                                 0     0     0     0   
>> ==============================
>> 
>> real	64m13.994s
>> user	1462m1.213s
>> sys	39m38.032s
>> 
>> 
>> There are interesting test failures on my machine, which I would address separately.
>
> Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Drop applications and fix the comment

Once again, the disconnect between Oracle and OpenJDK test definitions seems to be the problem for Oracle's side. Rectifying that disconnect might fall under the scope of this PR, but I have to point out that it is a courtesy of upstream open-source project to care about proprietary downstream definitions.

More to the point: since `tier4` as "catch-all-the-rest" was Igor's idea, I assumed that would be in agreement with Oracle's test definitions. Following this discussion, it seems I assumed wrong. So it puts me in a weird position to be between two Oracle engineers arguing about proprietary test definitions I cannot really know about, and have no decision power about. For all I care for OpenJDK, we might as well model `tier4` after what Oracle does, as to minimize confusion for Oracle engineers. But then again, I have no idea what Oracle means by `tier4`. So as the alternative, I can postpone this PR until you folks have a coherent view on this, or I can just give up on this PR and re-assign the RFE to Igor, assuming he is willing to work this out.

Tell me what you want me to do here.

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PR: https://git.openjdk.java.net/jdk/pull/5357