hg: code-tools/jtreg: 7902075: jtreg doesn't build if jh.jar doesn't contain signatures

[jonathan.gibbons at oracle.com]

Changeset: c0efd4ab54dc
Author:    jjg
Date:      2017-12-01 13:51 -0800
URL:       http://hg.openjdk.java.net/code-tools/jtreg/rev/c0efd4ab54dc

7902075: jtreg doesn't build if jh.jar doesn't contain signatures
Contributed-by: volker.simonis at gmail.com

! make/jtreg.gmk