encoding: extract stub for fast JSON escape
This moves JSON character maps to pure/charencode.py because they will be
used only when the fast-path fails.
journal: do not use atomictemp (
issue5338)
Writing journal files using `atomictemp` leads to quadratic performance that
could be problematic if automation runs many commands. Other logs like
blackbox does not use atomictemp, and journal logs are not critical for repo
correctness. So let's make them non-atomictemp.
Differential Revision: https://phab.mercurial-scm.org/D517
tests: add blank output lines to test-commandserver
This helps the import checker notice when a Python heredoc has
ended. It's not perfect, but it gets nasty quick and I think the
better fix would be to add a real parser for .t-tests, which will have
to wait.