hgignore: simply ignore all *.exe's everywhere
it's not like we're going to add any exe anywhere ever
tests: ignore pax_global_header in test-subrepo-git.t
Failure seen on hgbuildbot 2.4 and 2.5 after
1894dac619de.
Hide '../archive_x/s/pax_global_header' with same strange trick as in
5dda6c708138.
tests: remove GNU quoting in test-subrepo-deep-nested-change.t
Test failure on non-GNU systems introduced in
1894dac619de.