The current test directly uses invalidatblock to trigger
mempool re-entry of transactions. Unfortunately, the
behavior doesn't match what a real reorg would look like. As
a result you get surprising behavior such as the mempool
descendant chain limits being exceeded, or if a fork is
greater than 10 blocks deep, evicted block transactions stop
being submitted back into in the mempool.
Fix this by preparing an empty fork chain, and then
continuing with the logic, finally submitting the fork chain
once the rest of the test is prepared. This triggers a more
typical codepath.
Also, extend the descendant limit to 100, like ancestor
limit.
The previous diff touched most files in ./test/, so bump the headers to
avoid having to touch them again for a bump later.
-BEGIN VERIFY SCRIPT-
./contrib/devtools/copyright_header.py update ./test/
-END VERIFY SCRIPT-
substitutes "for x in range(N):" by "for _ in range(N):"
indicates to the reader that a block is just repeated N times, and
that the loop counter is not used in the body
