More informative error messages for non-Transferables.

LayoutTests/fast/workers/worker-onerror-09-expected.txt

Index: LayoutTests/fast/workers/worker-onerror-09-expected.txt
diff --git a/LayoutTests/fast/workers/worker-onerror-09-expected.txt b/LayoutTests/fast/workers/worker-onerror-09-expected.txt
new file mode 100644
index 0000000000000000000000000000000000000000..6349e5d4442e51a7fb018148c56258cab616b1f5
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+++ b/LayoutTests/fast/workers/worker-onerror-09-expected.txt
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+This tests that unhandled exceptions in postMessage() are delivered to 'worker.onerror'.
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+
+Page-level worker.onerror handler triggered:
+PASS errorEvent.message is "Uncaught TypeError: Failed to execute 'postMessage' on 'WorkerGlobalScope': Second argument is neither an array, nor does it have indexed properties."
+PASS stripURL(errorEvent.filename) is "[blob: URL]"
+PASS errorEvent.lineno is 3
+PASS errorEvent.colno is 9
+PASS errorEvent.error is null
+PASS successfullyParsed is true
+
+TEST COMPLETE
+