tests: stabilize test-fix.t on Windows `pwd` prints /tmp/... style paths, not C:\... needed for $TESTTMP to be substituted. In the final test, for whatever reason, Windows was missing EOL in the files and printing: [wdir] changedlines: printf: warning: ignoring excess arguments, starting with 'printf' even though it was trying to run: printf "Line ranges:\n"; printf "2 through 2\n"; I tried wrapping both :command and :linerange in `sh -c "..."`, and while that fixed the missing EOL, it missed the "2 through 2" output. Differential Revision: https://phab.mercurial-scm.org/D6852