Fix for calculation of event.path for closed mode shadow root

LayoutTests/fast/dom/shadow/event-path-closed-shadowroot2-expected.txt

+Event.path should include only unclosed nodes.
+The full event path should be (length=12):
+div#target, #shadow-root (open), div#div3_open, #shadow-root (closed),
+div#div2_closed, #shadow-root (open), div#host_open, div#host_closed,
+body, html, #document, window
+
+On #host_closed, #host_open, and #div2_closed,
+div#target, #shadow-root (open), div#div3_open, #shadow-root (closed)
+will be trimmed (length=8).
+
+
+Dispaching a click event on #target, listening on #host_closed.
+Got event.path for #host_closed:
+#div2_closed, [object ShadowRoot], #host_open, #host_closed, [object HTMLBodyElement], [object HTMLHtmlElement], [object HTMLDocument], [object Window], length: 8
+
+Dispaching a click event on #target, listening on #host_open.
+Got event.path for #host_open:
+#div2_closed, [object ShadowRoot], #host_open, #host_closed, [object HTMLBodyElement], [object HTMLHtmlElement], [object HTMLDocument], [object Window], length: 8
+
+Dispaching a click event on #target, listening on #div2_closed.
+Got event.path for #div2_closed:
+#div2_closed, [object ShadowRoot], #host_open, #host_closed, [object HTMLBodyElement], [object HTMLHtmlElement], [object HTMLDocument], [object Window], length: 8
+
+Dispaching a click event on #target, listening on #div3_open.
+Got event.path for #div3_open:
+#target, [object ShadowRoot], #div3_open, [object ShadowRoot], #div2_closed, [object ShadowRoot], #host_open, #host_closed, [object HTMLBodyElement], [object HTMLHtmlElement], [object HTMLDocument], [object Window], length: 12
+
+Dispaching a click event on #target, listening on #target.
+Got event.path for #target:
+#target, [object ShadowRoot], #div3_open, [object ShadowRoot], #div2_closed, [object ShadowRoot], #host_open, #host_closed, [object HTMLBodyElement], [object HTMLHtmlElement], [object HTMLDocument], [object Window], length: 12
+PASS successfullyParsed is true
+
+TEST COMPLETE
+