tests: perform a shallow copy instead of a deep copy Python 3 can't perform a deep copy because it looks like symbols in the locals() namespace are not deep-copyable. For the curious, somehow the deepcopy() is attempting to copy objects attached to the unittest.* functions for the running test! We don't use deepcopy() anywhere in the code base and a shallow object copy should be sufficient to test lock copying. Actually, I'm not sure why we even test this, as I couldn't find copy.copy() being used for lock copying either. Who knows. Differential Revision: https://phab.mercurial-scm.org/D5770

tests: make and use a new `svnurlof.py` helper for constructing svn urls The previous trick of a Python oneliner and some subshells is too hard to make portable, and this lets us consolidate some Windows-specific logic down to a single place. Differential Revision: https://phab.mercurial-scm.org/D5766

server: skip logging of ECONNRESET I believe this was exposed by 5492dc20, because the sending of the 500 would have already failed and prevented this logging. On Python 3, this will be a ConnectionResetError, which is a subtype of OSError, which is why we check for both OSError and socket.error. Bonus: this fixes a race in test-hgweb.t where sometimes the ECONNRESET wouldn't happen, because now we just don't log those errors. Differential Revision: https://phab.mercurial-scm.org/D5764