tests: filter out uninteresting log events Core has new ui.log() calls added (for tracking extension loading and performance, for example), but in test-discovery-obshashrange.t it produces a bunch of lines that are unrelated to the test. So we filter them out to not touch test output. This is inspired by 1de3364320af in core.

#require test-repo pyflakes

Copied from Mercurial core (60ee2593a270)

  $ cd "`dirname "$TESTDIR"`"

run pyflakes on all tracked files ending in .py or without a file ending
(skipping binary file random-seed)

  $ hg locate 'set:(**.py or grep("^#!.*python")) - removed()' 2>/dev/null \
  > | xargs pyflakes 2>/dev/null