added assume to skip errors when mono is not installed

dependency-check-core/src/test/java/org/owasp/dependencycheck/analyzer/AssemblyAnalyzerTest.java

@@ -62,6 +62,7 @@ public class AssemblyAnalyzerTest extends BaseTest {
             analyzer = new AssemblyAnalyzer();
             analyzer.accept(new File("test.dll")); // trick into "thinking it is active"
             analyzer.initialize();
+            Assume.assumeTrue("Mono is not installed, skipping tests.", analyzer.buildArgumentList() == null);
         } catch (Exception e) {
             if (e.getMessage().contains("Could not execute .NET AssemblyAnalyzer")) {
                 LOGGER.warn("Exception setting up AssemblyAnalyzer. Tests will be incomplete");