#784 Separate purge execution and purge task creation

- Delete accounts in PurgeExecutor, after permission check

src/test/java/fr/xephi/authme/datasource/AbstractResourceClosingTest.java

@@ -219,7 +219,7 @@ public abstract class AbstractResourceClosingTest {
 
             Object element = PARAM_VALUES.get(genericType);
             Preconditions.checkNotNull(element, "No sample element for list of generic type " + genericType);
-            if (List.class == parameterizedType.getRawType()) {
+            if (isAssignableFrom(parameterizedType.getRawType(), List.class)) {
                 return Arrays.asList(element, element, element);
             } else if (Set.class == parameterizedType.getRawType()) {
                 return new HashSet<>(Arrays.asList(element, element, element));
@@ -229,6 +229,11 @@ public abstract class AbstractResourceClosingTest {
         throw new IllegalStateException("Cannot build list for unexpected Type: " + type);
     }
 
+    private static boolean isAssignableFrom(Type type, Class<?> fromType) {
+        return (type instanceof Class<?>)
+            && ((Class<?>) type).isAssignableFrom(fromType);
+    }
+
     /* Initialize the map of test values to pass to methods to satisfy their signature. */
     private static Map<Class<?>, Object> getDefaultParameters() {
         HashedPassword hash = new HashedPassword("test", "test");