hg: jdk10/master: 8188090: Running tests from make causes spurious mercurial changes

[maurizio.cimadamore at oracle.com]

Changeset: 7513299d1cd0
Author:    mcimadamore
Date:      2017-09-28 11:20 +0100
URL:       http://hg.openjdk.java.net/jdk10/master/rev/7513299d1cd0

8188090: Running tests from make causes spurious mercurial changes
Summary: Fix relative path in test/TestCommon.gmk
Reviewed-by: erikj

! test/TestCommon.gmk