RFR: JDK-8243991 Use standard -Xss argument in java command line

[Magnus Ihse Bursie]

We should use the official -Xss argument[1] in command lines, instead of 
the non-standard -XX:ThreadStackSize.

Bug: https://bugs.openjdk.java.net/browse/JDK-8243991
WebRev: 
http://cr.openjdk.java.net/~ihse/JDK-8243991-fix-Xss-in-java-args/webrev.01

/Magnus

[1] 
https://docs.oracle.com/en/java/javase/14/docs/specs/man/java.html#extra-options-for-java