tests/test-revlog.t

largefiles: fix support for local largefiles while using share extension

Prior to revision 2a3f24786d09, largefiles were saved in the local repository,
even if it was using the share extension. After that change, all largefiles are
now stored in the shared repository. However, the backward compatibility for
existing largefiles already placed in the local repository was never tested,
and has been broken since.

Test for CVE-2016-3630

  $ hg init

  >>> open("a.i", "w").write(
  ... """eJxjYGZgZIAAYQYGxhgom+k/FMx8YKx9ZUaKSOyqo4cnuKb8mbqHV5cBCVTMWb1Cwqkhe4Gsg9AD
  ... Joa3dYtcYYYBAQ8Qr4OqZAYRICPTSr5WKd/42rV36d+8/VmrNpv7NP1jQAXrQE4BqQUARngwVA=="""
  ... .decode("base64").decode("zlib"))

  $ hg debugindex a.i
     rev    offset  length  delta linkrev nodeid       p1           p2
       0         0      19     -1       2 99e0332bd498 000000000000 000000000000
       1        19      12      0       3 6674f57a23d8 99e0332bd498 000000000000
  $ hg debugdata a.i 1 2>&1 | egrep 'Error:.*decoded'
  (mercurial.mpatch.)?mpatchError: patch cannot be decoded (re)