Append argLine arguments instead of overriding

This change in the configuration of maven-surefire-plugin is required to work correctly with JaCoCo usage in downstream projects.

Author: imagejan

pom.xml

@@ -495,7 +495,7 @@
 					own property 'scijava.surefire.args' to specify those options.
 					-->
 					<configuration>
-						<argLine>-Xms512m -Xmx512m -Dapple.awt.UIElement="true" ${scijava.surefire.args}</argLine>
+						<argLine>@{argLine} -Xms512m -Xmx512m -Dapple.awt.UIElement="true" ${scijava.surefire.args}</argLine>
 					</configuration>
 				</plugin>