tests: fix the flaky test test-logtoprocess.t The main change is that we're waiting for the [touched] file to appear for 5 seconds instead of 0.1 seconds. Also, instead of implementing wait-on-file from scratch, we use the existing one from testlib/ that works well.

[workspace]
members = ["hg-core", "hg-cpython", "rhg"]
exclude = ["chg", "hgcli"]