tests: avoid tests related to directory permission if running with fsmonitor

tests: add extra output for fsmonitor at checking under .hg

tests: add extra output for fsmonitor at showconfig

tests: take extra care for fsmonitor at enabling incompatible extension This is worthwhile, because these tests don't focus mainly on using incompatible extensions itself.

tests: remove meaningless entries from blacklist for fsmonitor IMHO, these tests were listed up in blacklist at 3b67f27bb908, because fsmonitor extension wasn't correctly installed before actual testing at that revision (this issue was fixed by 776fd2e2cf5a).

tests: remove meaningless comment from blacklist for fsmonitor These tests can run successfully since fe0667cc521e.

test-https: stabilize for Windows A leading '/' without a following drive letter is resolved to the location of the MSYS installation. These could be collapsed into a single line of output, but this seems more self documenting.

tagmerge: use workingfilectx to write merged tags This function already does an excellent job of reading from context objects; we simply need to change the single write call to eliminate all uses of the wvfs. As with past changes, the effect should be a no-op but opens the door to in-memory merge later by using different context objects.

run-tests: add color to output if pygments is available The output of run-tests has no formatting by default, which hampers readability. This patch colors the diff output when pygments is available. To avoid coloring even when pygments is available, use --color never.

win32: work around a WinError problem handling HRESULT types I ran into this ctypes bug while working with the Crypto API. While this could be an issue with any Win32 API in theory, the handful of things that we call are older functions that are unlikely to return COM errors, so I didn't retrofit this everywhere.