test-copies: add a `q` branch similar to the `e` but on the new files
This branch will be used to create merge case that mirror ones involving the `e` branch.
Differential Revision: https://phab.mercurial-scm.org/D10056
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# Avoid interference from actual test env:
unset HGTEST_JOBS
unset HGTEST_TIMEOUT
unset HGTEST_PORT
unset HGTEST_SHELL