test-run-tests: accept more levels of precision and trailing ws (issue4440)

simplejson produces slightly different output from the built-in json
module, specifically:
  * It uses 0.000 instead of 0.0000
  * It likes to put a trailing space after a comma

This change works around both of those variations.

--HG--
branch : stable
extra : rebase_source : da024d34b75f33b1bad8468d249c58d84a474c9e
rebase: fix rebase with no common ancestors (issue4446)

The new rebase revset didn't check for the case when there are no common
ancestors. Now it does. The new behavior should be the same as the pre-3.2
behavior. Added a test.

--HG--
branch : stable
extra : rebase_source : 0d009b83b754be266d0c94b336ac34d6875c8f82
merge with stable