In my prior two save core API's, I experimented on how to save stacks
with the new API. I incorrectly left these in, as the existing
`m_thread_by_range_end` was the correct choice.
I have removed the no-op collection, and moved to use the proper one.
It's worth noting this was not caught by testing because we do not
verify where the items are contained in the minidump. This would require
a test being aware of how minidumps are structured, or adding a textual
tool that we can then scan the output of.
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