revlog: fix pure version of _partialmatch() to include nullid Before this patch, test-issue842.t and a few more tests fail when they try to refer to the null revision by using a "000.." prefix of it (or because they use the "shortest" template function which internally does that). This should have been part of my a3dacabd476b (index: don't allow index[len(index)] to mean nullid, 2018-07-20), but I had forgotten to update another part of the pure code there, so it didn't fail until a1f934573c0b (parsers: adjust pure-python version to mimic a3dacabd476b, 2018-08-09) and 65d5de1169dd (revlog: fix pure nodemap to not access missing index entry, 2018-08-17) fixed the other things I had missed. Differential Revision: https://phab.mercurial-scm.org/D4332