tests/svnurlof.py

filemerge: move check for identical sides out of filemerge()

`filemerge.filemerge()` returns `None` if no merge was necessary
because the two sides were identical. I don't think it should be that
function's responsibility to handle that case; we should ideally not
even call `filemerge.filemerge()` if the two inputs identical. This
patch therefore moves the check out to the caller (`mergestate.py`).

The largefiles test changed because we now notice that the two sides
made the same change, so we don't consider it a merge. Also note that
the new message better matches the line above it in the test output.

Differential Revision: https://phab.mercurial-scm.org/D12154

from __future__ import absolute_import, print_function
import sys

from mercurial import (
    pycompat,
    util,
)


def main(argv):
    enc = util.urlreq.quote(pycompat.sysbytes(argv[1]))
    if pycompat.iswindows:
        fmt = 'file:///%s'
    else:
        fmt = 'file://%s'
    print(fmt % pycompat.sysstr(enc))


if __name__ == '__main__':
    main(sys.argv)