RFR: JDK-8220639 Need a way to augment JTREG_LAUNCHER_OPTIONS from command-line

Mon Jun 15 15:56:48 UTC 2020

It turned out that it was not possible to send arguments directly to the 
java that launches jtreg, something that was needed, especially to 
change the output limit using Djavatest.maxOutputSize.

This patch adds JTREG=LAUNCHER_OPTIONS=xxx to pass generic options to 
the launcher. Also, for the specific case of changing the max output 
size, it adds JTREG=MAX_OUTPUT=nnn.

All these new options made me realize there's no way apart from reading 
the code to know what options are available, so I added a help system, 
and documented this in "make help". Now you can get:

$ make test JTREG=help
Building target 'test' in configuration 'linux-x64'
Valid keywords for JTREG:
JOBS TIMEOUT_FACTOR FAILURE_HANDLER_TIMEOUT TEST_MODE ASSERT VERBOSE 
RETAIN MAX_MEM RUN_PROBLEM_LISTS RETRY_COUNT MAX_OUTPUT OPTIONS 
JAVA_OPTIONS VM_OPTIONS KEYWORDS EXTRA_PROBLEM_LISTS AOT_MODULES 
LAUNCHER_OPTIONS.
RunTests.gmk:292: *** Re-run without 'help' to continue. Stop.

Finally, I fixed some broken comments regarding AOT that I noticed while 
fixing this.

Bug: https://bugs.openjdk.java.net/browse/JDK-8220639
WebRev: 
http://cr.openjdk.java.net/~ihse/JDK-8220639-add-jtreg-launcher-options/webrev.01

/Magnus