py3: fix type of default username

py3: read/write plain lock file in binary mode A lock file shouldn't contain '\n', so this isn't a BC.

util: stop calling os.stat_float_times() It had Python-wide side effects, and it disappears in 3.7.0. As of this change, we're mostly working on 3.7.0b2. There are a few worrying failures, mostly around regular expressions, but we'll have to tackle those separately. Differential Revision: https://phab.mercurial-scm.org/D2697

cleanup: use stat_result[stat.ST_MTIME] instead of stat_result.st_mtime The latter is floating point by default, and we've been doing os.stat_float_times(False). Unfortunately, os.stat_float_times was removed between Python 3.7.0a1 and 3.7.0b2, so we have to stop using it. Differential Revision: https://phab.mercurial-scm.org/D2696

osutil: implement minimal __getitem__ compatibility on our custom listdir type We previously declined to do this, but the removal of the deprecated os.stat_float_times() method in Python 3.7 forces our hand. Differential Revision: https://phab.mercurial-scm.org/D2695

hgweb: adapt to socket._fileobject changes in Python 3 Differential Revision: https://phab.mercurial-scm.org/D2688

debugcommands: fix some %r output with bytestr() wrappers Almost fixes test-merge-tools.t. I think the remaining failure there is due to some overspecified tempfile names. Differential Revision: https://phab.mercurial-scm.org/D2675

tests: add test for issue 5494 but with --collapse This was not fixed, so the test case currently demonstrates the breakage. Differential Revision: https://phab.mercurial-scm.org/D2714