hg: jdk10/sandbox/nashorn: 8186095: upgrade to jtreg 4.2 b08

[chris.hegarty at oracle.com]

Changeset: 6b8802e1dab8
Author:    iignatyev
Date:      2017-08-20 20:36 -0700
URL:       http://hg.openjdk.java.net/jdk10/sandbox/nashorn/rev/6b8802e1dab8

8186095: upgrade to jtreg 4.2 b08
Reviewed-by: rriggs, mchung, dholmes, iklam

! test/TEST.ROOT