Update Sizzle: focus test was failing if browser window was not in focus

diff --git a/src/sizzle b/src/sizzle
index f0dc09b83356e8bf8adeeb555e09077a10af2dc6..56d3b2f2a7843248a9fa2d8e243d47defb373446 160000 (submodule)
--- a/src/sizzle
+++ b/src/sizzle
@@ -1 +1 @@
-Subproject commit f0dc09b83356e8bf8adeeb555e09077a10af2dc6
+Subproject commit 56d3b2f2a7843248a9fa2d8e243d47defb373446