hg: jigsaw/jake/langtools: Update jtreg required version to 4.2 b07

[mandy . chung]

Changeset: a564c0126103
Author:    mchung
Date:      2017-04-04 22:09 -0700
URL:       http://hg.openjdk.java.net/jigsaw/jake/langtools/rev/a564c0126103

Update jtreg required version to 4.2 b07

! test/TEST.ROOT