tests/test-paths

Fix --blacklist when --jobs > 1 in run_tests.py.

The options parsing logic replaces the options.blacklist initial value,
a list of filenames, with a dict of test names to filenames.  When
runchildren rebuilds the command line to launch child processes the dict
is flattened and provided as a malformed argument when a filename is
expected.

Fix is to remove the blacklist option from child invocations since the
filtering is handled in the parent anyway.

#!/bin/sh
hg init a
hg clone a b
cd a
echo '[paths]' >> .hg/hgrc
echo 'dupe = ../b' >> .hg/hgrc
hg in dupe | fgrep '../'
cd ..
hg -R a in dupe | fgrep '../'
true