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.
% no bookmarks
no bookmarks set
% set bookmark X
% list bookmarks
* X -1:000000000000
% update to bookmark X
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
% list bookmarks
* X -1:000000000000
% rename
% list bookmarks
* Z -1:000000000000
% new bookmark Y
% list bookmarks
* Y -1:000000000000
Z -1:000000000000
% commit
% list bookmarks
* Y 0:719295282060
Z -1:000000000000
% delete bookmarks
% list bookmarks
no bookmarks set
% update to tip
0 files updated, 0 files merged, 0 files removed, 0 files unresolved