tests/histedit-helpers.sh

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

fixbundle() {
    grep -v 'saving bundle' | grep -v 'saved backup' | \
        grep -v added | grep -v adding | \
        grep -v "unable to find 'e' for patching" | \
        grep -v "e: No such file or directory" | \
    cat
}