fix parameter ordering in windows.cpp's MySystem::visit

It's amazing to me that ebp and esp have been swapped for over three
years without anybody noticing.  It was dumb luck that the Trace test
(which is designed to catch just such a thing) happened to fail when I
ran the whole suite, and further investigation revealed that it was
failing maybe five percent of the times it was run.  Now we know why.
fix Windows x86_64 build regression due to unspecified AVIAN_TARGET_FORMAT
allow extra flags to be passed to make in ci.sh