hg: code-tools/jtreg: 7902417: jtreg build with build-all.sh should work on cygwin

[jonathan.gibbons at oracle.com]

Changeset: 484baaa88377
Author:    jjg
Date:      2019-03-07 11:28 -0800
URL:       http://hg.openjdk.java.net/code-tools/jtreg/rev/484baaa88377

7902417: jtreg build with build-all.sh should work on cygwin
Contributed-by: christoph.langer at sap.com

! make/Rules.gmk
! make/build-all.sh