[Worker] Test using FileWriter.seek to write overlapping existing data in a file.

On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".

Starting worker: ../resources/file-writer-write-overlapped.js
[Worker] starting test
PASS [Worker] Negative seek validated.
PASS [Worker] Positive seek validated.
PASS [Worker] Nonextending write validated.
PASS [Worker] All writes verified.
PASS successfullyParsed is true

TEST COMPLETE