Fix undetected runtime dependency usage problem from previous commit

In module 'tests', our tests need Ant launcher. Hence, dependency
ant:ant-launcher was re-added to the POM (with test scope this time)
and Maven Dependency plugin configured to regard it as a used
dependency and not falsely report it as unused.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

tests/pom.xml

@@ -85,6 +85,13 @@
 			<version>${project.version}</version>
 			<scope>test</scope>
 		</dependency>
+		<dependency>
+			<!-- Identical to lib/ant/lib/ant-launcher.jar, a former system-scoped dependency -->
+			<groupId>ant</groupId>
+			<artifactId>ant-launcher</artifactId>
+			<version>${lib.ant.version}</version>
+			<scope>test</scope>
+		</dependency>
 	</dependencies>
 
 	<build>
@@ -100,6 +107,16 @@
 						</includes>
 					</configuration>
 				</plugin>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-dependency-plugin</artifactId>
+				<configuration>
+					<usedDependencies>
+						<!-- The tests need this during runtime, even though no direct usage is in our classes -->
+						<usedDependency>ant:ant-launcher</usedDependency>
+					</usedDependencies>
+				</configuration>
+			</plugin>
 			</plugins>
 	</build>