tests: prove that `hg init` works with Python 3 The previous patch made `hg init` work!

pycompat: custom implementation of urllib.parse.quote() urllib.parse.quote() accepts either str or bytes and returns str. There exists a urllib.parse.quote_from_bytes() which only accepts bytes. We should probably use that to retain strong typing and avoid surprises. In addition, since nearly all strings in Mercurial are bytes, we probably don't want quote() returning unicode. So, this patch implements a custom quote() that only accepts bytes and returns bytes. The quoted URL should only contain URL safe characters which is a strict subset of ASCII. So `.encode('ascii', 'strict')` should be safe.

pycompat: alias urllib symbols directly urllib.request imports a bunch of symbols from other urllib modules. We should map to the original symbols not the re-exported ones because this is more correct. Also, it will prevent an import of urllib.request if only one of the lower-level symbols/modules is needed.

tests: clean up bad extension The presence of the "babar" extension breaks subsequent tests. So delete the file and create an empty one to return the config to sanity.

perf: perform a garbage collection before each iteration Currently, no explicit garbage collection is performed when running the microbenchmarks in `hg perf`. I think this is wrong because garbage collection can have a significant impact on execution times. And, if gc is triggered via the default heuristics, it will fire effectively randomly during subsequent benchmark iterations due to variable amount of garbage left over from previous runs. Running a gc before invoking the measured function will help ensure state is more consistent across all iterations.

formatter: support json formatting of long type By luck, we appear to not pass any long instances into the JSON formatter. I suspect this will change with all the Python 3 porting work. Plus I have another series that will convert some ints to longs that triggers this.