tests: invoke hg command indirectly from shell script to run on Windows Before this patch, test-tag.t can't run successfully on Windows, because: - quoted hg command ('"hg"') prevents "hg.bat" from working correctly (only at testing with pure Python build) "%~f0" and "%~dp0hg" in "hg.bat" cause unexpected result in this case. BTW, quoted "\path\to\hg" works correctly. - "`pwd`" in the command line is expanded unexpectedly not "C:\path\to\TESTTMP" but "C;C:\path\to\TESTTMP"