RFR: 8273314: Add tier4 test groups [v3]

[Aleksey Shipilev]

> 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

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5357/files
  - new: https://git.openjdk.java.net/jdk/pull/5357/files/afb77062..160c13c7

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5357&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5357&range=01-02

  Stats: 3 lines in 2 files changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5357.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5357/head:pull/5357

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