tests: put temporary file outside the working directory for test portability
test-largefiles-update.t creates temporary file exec-bit.patch inside
the working directory for no-execbit platform specific test, but
subsequent tests aren't aware of it.
On execbit platform, subsequent tests can run successfully, because
exec-bit.patch isn't created.
But on no-execbit platform, this temporary file makes subsequent tests
show "? exec-bit.patch" at each "hg status".
# See http://EditorConfig.org for the specification
root = true
[*.py]
indent_size = 4
indent_style = space
trim_trailing_whitespace = true
[*.{c,h}]
indent_size = 8
indent_style = tab
trim_trailing_whitespace = true