Gracefully handle the case when a DISTDIR already exists
Run block tester and test suite on Windows too (only on Jenkins)
Fix port binding by listening on port $BASHPID
Merge pull request #3174 from TheBlueMatt/master

Re-enable Jenkins and run more tests on Jenkins than pull-tester gets
Missed an RPC port
Merge pull request #3175 from TheBlueMatt/master

Missed RPC port