tests: Add focus_visibility_change test

This test verifies the behavior of focus when its visibility is changed.

tests/tests/swfs/avm1/focus_visibility_change/output.txt

@@ -0,0 +1,45 @@
+===== clip
+Object: _level0.clip
+Made visible
+Focus changed
+  old: null
+  new: _level0.clip
+Focus: _level0.clip
+Focus changed
+  old: _level0.clip
+  new: null
+Made invisible
+Focus: null
+Made visible
+Focus: null
+Made invisible
+===== text
+Object: _level0.text
+Made visible
+Focus changed
+  old: null
+  new: _level0.text
+Focus: _level0.text
+Focus changed
+  old: _level0.text
+  new: null
+Made invisible
+Focus: null
+Made visible
+Focus: null
+Made invisible
+===== button
+Object: _level0.button
+Made visible
+Focus changed
+  old: null
+  new: _level0.button
+Focus: _level0.button
+Focus changed
+  old: _level0.button
+  new: null
+Made invisible
+Focus: null
+Made visible
+Focus: null
+Made invisible

tests/tests/swfs/avm1/focus_visibility_change/test.as

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+var listener = new Object();
+listener.onSetFocus = function(oldFocus, newFocus) {
+    trace("Focus changed");
+    trace("  old: " + oldFocus);
+    trace("  new: " + newFocus);
+};
+Selection.addListener(listener);
+
+function testObject(obj) {
+    trace("Object: " + obj);
+    obj._visible = true;
+    trace("Made visible");
+    obj.focusEnabled = true;
+    Selection.setFocus(obj);
+    trace("Focus: " + Selection.getFocus());
+    obj._visible = false;
+    trace("Made invisible");
+    trace("Focus: " + Selection.getFocus());
+
+    obj._visible = true;
+    trace("Made visible");
+    trace("Focus: " + Selection.getFocus());
+    obj._visible = false;
+    trace("Made invisible");
+}
+
+var clip = _root.createEmptyMovieClip("clip", 10);
+var text = _root.createTextField("text", 11, 0, 0, 150, 20);
+text.type = "input";
+var button = _root.attachMovie("CustomButton", "button", 12);
+
+trace("===== clip");
+testObject(clip);
+
+trace("===== text");
+testObject(text);
+
+trace("===== button");
+testObject(button);

tests/tests/swfs/avm1/focus_visibility_change/test.toml

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+num_ticks = 1