test-run-test: use explicit variables to clarify paths Since $TESTTMP and $TESTDIR are defined for both the main scope and the test run during the test, the situation get confusing. To work around that, we define some new, explicit, variables with the values we needs to keep track of. Differential Revision: https://phab.mercurial-scm.org/D11034

run-tests: also catch double-escapes for $TESTTMP On Windows the `$TESTTMP` string "repr" is different than its value, because `\` become `\\`. We introduce a new `$STR_REPR_TESTTMP` substitution to match that too. Differential Revision: https://phab.mercurial-scm.org/D11001

ci-windows: introduce manual windows CI Note: most of the foundational work of this commit was done by Matt Harbison, but enough has changed that I don't feel comfortable sending this patch as his. In our quest to remove Python 2 from Mercurial, we need to get Windows CI going to check that Python 3 support is up to an acceptable standard. This is the first step: adding a manual step to run a full Windows CI, with a certain definition of "full" since some things are not installed yet, like SVN. Differential Revision: https://phab.mercurial-scm.org/D11025