RFR: 8323515: Create test alias "all" for all test roots

[Aleksey Shipilev]

Since recent work to improve `tier4` performance, we actually test `tier{1,2,3,4}` often, which includes all the tests in current tree. It would be more convenient to just have the `all` test group/alias, so that we can do `make test TEST=all`. This also gives a parallelism / run time benefit, as we do not wait for tests in each tier to complete before moving to next tier. 

Sample run on out-of-the-box Linux x86_64 fastdebug is below. For some environments one also needs to supply a few keywords like `!printer` to skip tests that cannot complete without failure due to misconfiguration. I left the keywords as is to show how would a failing run look. There is also an existing shortcut in build system that allows to run this with `make test-all`.


% make test TEST=all

Test selection 'all', will run:
* jtreg:test/hotspot/jtreg:all
* jtreg:test/jdk:all
* jtreg:test/langtools:all
* jtreg:test/jaxp:all
* jtreg:test/lib-test:all

(...about 6 hours later...)

==============================
Test summary
==============================
   TEST                                              TOTAL  PASS  FAIL ERROR   
>> jtreg:test/hotspot/jtreg:all                       6731  6702    29     0 <<
>> jtreg:test/jdk:all                                 9962  9951    11     0 <<
   jtreg:test/langtools:all                           4469  4469     0     0   
   jtreg:test/jaxp:all                                 513   513     0     0   
   jtreg:test/lib-test:all                              32    32     0     0   
==============================
TEST FAILURE

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

Commit messages:
 - Fix

Changes: https://git.openjdk.org/jdk/pull/17422/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17422&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8323515
  Stats: 41 lines in 5 files changed: 34 ins; 5 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/17422.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17422/head:pull/17422

PR: https://git.openjdk.org/jdk/pull/17422