run-tests: pass temp dir into Test.__init__
This patch starts a mini series of moving arguments to Test.__init__
from semi-complex data structures (such as the command options) to named
arguments. This will allow Test instances to be more easily instantiated
from other contexts. This improves the ability to run Mercurial tests in
new and different environments.
ERROR: FIXME: This is a known failure of filelog.size for data starting with \1\n
OK.