similar: do not look up and create filectx more than once
Benchmark with 50k added/removed files, on tmpfs:
$ hg addremove --dry-run --time -q
previous: real 16.070 secs (user 14.470+0.000 sys 1.580+0.000)
this patch: real 12.420 secs (user 11.120+0.000 sys 1.280+0.000)
# 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