Summary:
Let's switch to xdiff for its better diff quality and performance!
The test changes demonstrate xdiff's better diff quality.
Reviewed By: ryanmce
Differential Revision: D7135206
fbshipit-source-id: 1775df6fc0f763df074b4f52779835d6ef0f3a4e
Summary:
The next test is going to switch bdiff to xdiff. This diff adds related tests
so we can clearly how xdiff improves the diff quality.
It also solves [issue5091](https://bz.mercurial-scm.org/5091) because xdiff
will shift hunks up and down to group them together. So that was also added as
a test. Although in a more complex case where the hunks are separated by some
common lines (ex. "Y"), xdiff won't help either.
Reviewed By: ryanmce
Differential Revision: D7147444
fbshipit-source-id: 3605290b5dfdfc7b8b004b38c7f7ee9534915380
