rust-matchers: fix quadratic complexity in `FileMatcher`
Concretely, this command:
```
$ echo hg up -r <nodeid>; time hg revert dir1 dir2 -r <othernode> --debug
hg up -r <nodeid>
real 0m14.690s
user 0m14.766s
sys 0m5.430s
```
was much slower despite using 16 cores before this change.
The approach taken here is the same one used in match.py, in exactmatcher.
This changeset was originally written by Valentin Gatien-Baron in a private
repository.
I have redacted the commit message and did a minor clean up of the code.
Test update.requiredest
$ cd $TESTTMP
$ cat >> $HGRCPATH <<EOF
> [commands]
> update.requiredest = True
> EOF
$ hg init repo
$ cd repo
$ echo a >> a
$ hg commit -qAm aa
$ hg up
abort: you must specify a destination
(for example: hg update ".::")
[10]
$ hg up .
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ HGPLAIN=1 hg up
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg --config commands.update.requiredest=False up
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd ..
Check update.requiredest interaction with pull --update
$ hg clone repo clone
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd repo
$ echo a >> a
$ hg commit -qAm aa
$ cd ../clone
$ hg pull --update
abort: update destination required by configuration
(use hg pull followed by hg update DEST)
[10]
$ cd ..
update.requiredest should silent the "hg update" text after pull
$ hg init repo1
$ cd repo1
$ hg pull ../repo
pulling from ../repo
requesting all changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 1 files
new changesets 8f0162e483d0:048c2cb95949