Initialize Flogger backend in TestLoggingActivator#configureLogging

Instead of initializing the backend in ConfigSuite, initialize it in
in TestLoggingActivator#configureLogging. This allows the log config
to also be properly configured for test classes that inherit from the
GerritBaseTests; TestLoggingActivator#configureLogging is invoked in
the @BeforeClass annotated method.

Bug: Issue 12673
Change-Id: I65930c0ee80b597d87578c49a5daed80d2e13b6a

java/com/google/gerrit/testing/ConfigSuite.java

@@ -104,10 +104,6 @@ import org.junit.runners.model.InitializationError;
  * field annotated with {@code @ConfigSuite.Name}.
  */
 public class ConfigSuite extends Suite {
-  static {
-    FloggerInitializer.initBackend();
-  }
-
   public static final String DEFAULT = "default";
 
   @Target({METHOD})

java/com/google/gerrit/testing/TestLoggingActivator.java

@@ -83,6 +83,7 @@ public class TestLoggingActivator {
 
   public static void configureLogging() {
     LogManager.resetConfiguration();
+    FloggerInitializer.initBackend();
 
     PatternLayout layout = new PatternLayout();
     layout.setConversionPattern("%-5p %c %x: %m%n");