tests: add tests for `hg evolve --continue` This patch adds a new test file containing tests for `hg evolve --continue`. The test file still does not contains all the tests related to `hg evolve --continue` as one of the case is broken which needs to be fixed first. The case is when resolving a conflicting evolve results in empty wdir. Next patch will fix the traceback and then a later patch will add more tests.

syntax: re
/figures/[^/]+\.png$
^html/
\.pyc$
~$
\.swp$
\.orig$
\.rej$
^tests/.*\.err$
^tests/easy_run.sh$
^build/
^dist/
^MANIFEST$
^docs/tutorials/.*\.rst$
\.ico$
tests/\.testtimes

^docs/training/graphs/
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^docs/training/index.html
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