Add additional layout tests for MediaKeySession.keyStatuses

LayoutTests/media/encrypted-media/encrypted-media-keystatuses-multiple-updates-expected.txt

Index: LayoutTests/media/encrypted-media/encrypted-media-keystatuses-multiple-updates-expected.txt
diff --git a/LayoutTests/media/encrypted-media/encrypted-media-keystatuses-multiple-updates-expected.txt b/LayoutTests/media/encrypted-media/encrypted-media-keystatuses-multiple-updates-expected.txt
new file mode 100644
index 0000000000000000000000000000000000000000..83f3915a2a1a35aca42e9838b00c317ae860c85c
--- /dev/null
+++ b/LayoutTests/media/encrypted-media/encrypted-media-keystatuses-multiple-updates-expected.txt
@@ -0,0 +1,32 @@
+EVENT(message)
+EVENT(keystatuseschange)
+for (var entry of keyStatuses)
+123, usable
+for (var key of keyStatuses.keys())
+123
+for (var value of keyStatuses.values())
+usable
+for (var entry of keyStatuses.entries())
+123, usable
+keyStatuses.forEach()
+123, usable
+EVENT(keystatuseschange)
+for (var entry of keyStatuses)
+123, usable
+4567890, usable
+for (var key of keyStatuses.keys())
+123
+4567890
+for (var value of keyStatuses.values())
+usable
+usable
+for (var entry of keyStatuses.entries())
+123, usable
+4567890, usable
+keyStatuses.forEach()
+123, usable
+4567890, usable
+This is a testharness.js-based test.
+PASS Verify MediaKeySession.keyStatuses with multiple updates. 
+Harness: the test ran to completion.
+