Make output reproducible

[Jake-Shadle]

The SDK headers for the Desktop and Store variants contain many of the exact same files between them, so we only write one, but since this is running in parallel it's non-determinstic which one will get written, so we need to make it deterministic. It would also be a good idea to go ahead and actually verify that the files also have the same exact content as well. See this post for the original issue.

[K900]

In addition to the threading issues, the deduplication algorithm uses a hashmap right now, and those are seeded independently on each run, so the output is non-deterministic even with one thread.