hg: jigsaw/jake/jdk: Bump jtreg requiredVersion to 4.2

[mandy . chung]

Changeset: 31d2982578fe
Author:    mchung
Date:      2016-03-15 12:01 -0700
URL:       http://hg.openjdk.java.net/jigsaw/jake/jdk/rev/31d2982578fe

Bump jtreg requiredVersion to 4.2

! test/TEST.ROOT