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

Progress: 
 a) `hotspot:tier4` still runs cleanly, and a bit faster due to recent `vmTestbase` parallelism improvements.
 b) `jdk:tier4` has a lot of failures in headful mode, probably because the tests do not like to run in parallel, see for example #5533. It would take a while to resolve for all GUI tests. If we are in agreement that current `tier4` definition is good, maybe it would be proper to integrate this PR, and then make `tier4` clean for headful mode?

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