test-copies: introduce merge chains test for the P/Q merges This is similar to the chaining test we have for the A/E merges. The current result of this tests is wrong, as for the other test of the same familly. This will be fixed by a later changesets. Differential Revision: https://phab.mercurial-scm.org/D10059

test-copies: add a case involving the `b` and a new `r` branch That case involve a branch overwriting copies information from the other one. It is similar to the `mBFm` / `mFBm` case except this case actual content merge is involved too. Differential Revision: https://phab.mercurial-scm.org/D10058

test-copies: introduce case combining the `p` and `q` branch That case involves conflicting copies information from each branch. It is similar to the `mAEm` / `mEAm` case except this case actual content merge is involved too. Differential Revision: https://phab.mercurial-scm.org/D10057

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

test-copies: add a `p` branch similar to the `a` but on the new files This branch will be used to create merge case that mirror ones involving the `a` branch. Differential Revision: https://phab.mercurial-scm.org/D10055

test-copies: move the new files in the `i` branch The initial branch is moving some of the "same content" file around. We do the same for the "different content" before start to implement more tests. The new files have harmless impact of various existing tests. Differential Revision: https://phab.mercurial-scm.org/D10054

test-copies: add 3 new files with their own content The new `p`, `q` and `r` file mirror the `a`, `b` and `h` but with different content for each files. This will be used to create "mirror" test case that involve actual merge happening. For now, we only add the file to keep patches small and easier to review. Differential Revision: https://phab.mercurial-scm.org/D10053

test-copies: introduce merge chaing test for the A/E + change tests This is similar to the chaining test we have for the A/E merges (without change). The current result of this tests is wrong, as for they "without change counter part". This will be fixed by a later changesets. Differential Revision: https://phab.mercurial-scm.org/D10052

test-copies: add a "change during merge" variant to the A+E test Checks inline comment for details.

test-copies: filter out the linkrev part of `debugindex` It is not really useful for the tests and is a large source of churn when adding more revisions to the tests. Differential Revision: https://phab.mercurial-scm.org/D10050