Ant can now ignore unit tests matching a pattern

To temporarily ignore unit tests matching a specific pattern,
run the build scripts like this:

$ JUNIT_EXCLUDE_TESTS='**/pqc/**' sh build1-8+ test

This example ignores the pqc unit tests, using Ant's ** wildcard
to match multiple paths.

As the changes were made to the core bc+-build.xml Ant script, they
should work with any of the build1-* shell scripts.

ant/bc+-build.xml

@@ -986,6 +986,7 @@
             <batchtest todir="${artifacts.reports.xml.dir}" unless="testcase">
                 <fileset dir="${test.target.src.dir}">
                     <include name="**/AllTests.java" />
+                    <exclude name="${env.JUNIT_EXCLUDE_TESTS}" if="env.JUNIT_EXCLUDE_TESTS" />
                 </fileset>
             </batchtest>
         </junit>