Modifies few gc related layout tests to work with ignition.

third_party/WebKit/LayoutTests/fast/xpath/xpath-snapshot-result-should-mark-its-nodeset.html

Index: third_party/WebKit/LayoutTests/fast/xpath/xpath-snapshot-result-should-mark-its-nodeset.html
diff --git a/third_party/WebKit/LayoutTests/fast/xpath/xpath-snapshot-result-should-mark-its-nodeset.html b/third_party/WebKit/LayoutTests/fast/xpath/xpath-snapshot-result-should-mark-its-nodeset.html
index aae0b63bbc6978383f87ee1f922651ab47ceb6a1..3028a3d04ea27bcdd77c86c6fe3db6e577b370b5 100644
--- a/third_party/WebKit/LayoutTests/fast/xpath/xpath-snapshot-result-should-mark-its-nodeset.html
+++ b/third_party/WebKit/LayoutTests/fast/xpath/xpath-snapshot-result-should-mark-its-nodeset.html
@@ -18,9 +18,17 @@
 
         function test(type)
         {
-            var result = document.evaluate("//div", document.documentElement, null, type, null);
-            result.snapshotItem(0).foo = "PASS";
-            document.body.removeChild(result.snapshotItem(0));
+            var result;
+            function initialize() {
+                result = document.evaluate("//div", document.documentElement, null, type, null);
+                result.snapshotItem(0).foo = "PASS";
+                document.body.removeChild(result.snapshotItem(0));
+            }
+
+            // Do initialization work in an inner function to avoid references
+            // to objects remaining live on this function's stack frame
+            // (http://crbug.com/595672/).
+            initialize();
             gc();
             var console = document.getElementById("console");
             console.appendChild(document.createTextNode(result.snapshotItem(0).foo));