hg: code-tools/jtharness: (regression tests) temporarily removing 'skipnontests' batchtest's attribute not supported by Ant 1.8

[dmitry.bessonov at oracle.com]

Changeset: 0466a4758687
Author:    dbessono
Date:      2020-01-10 14:17 +0000
URL:       https://hg.openjdk.java.net/code-tools/jtharness/rev/0466a4758687

(regression tests) temporarily removing 'skipnontests' batchtest's attribute not supported by Ant 1.8

! build/build.xml