run-tests: add env dict to isolate test environment
run-tests: use env dict to kill daemons
tests: avoid writing files to HGTMP
run-tests: write tmp paths into env copy
run-tests: move HGPORT setting to env
run-tests: move DAEMON_PIDS to env
run-tests: move HGRCPATH to env
run-tests: move environment creation to a separate function
run-tests: move most of remaining environment tweaks
run-tests: simplify env deletion
run-tests: move more variables to env
run-tests: add abort flag

This will be used to help threads clean up gracefully
run-tests: introduce threadtmp directory
run-tests: use count to calculate port to use

This will keep threads from using the same server ports
run-tests: introduce thread scheduler
run-tests: schedule largest tests first
run-tests: remove runchildren, now unused
run-tests: drop options.child and users
run-tests: drop unused resultslock
run-tests: sort certain slow tests earlier by keyword

There are a few tests that evade the size heuristic