tags-cache: directly perform a monimal walk for hgtagsfnodescache warming
We do something narrower than the path retrieving data. So lets use dedicated
code instead.
This provides further useful speedup:
### data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog
# benchmark.name = hg.debug.debug-update-cache
# bin-env-vars.hg.flavor = default
# bin-env-vars.hg.py-re2-module = default
# benchmark.variants.pre-state = warm
before-this-series: 19.947581
skip-fnode-filter: 18.916804 (-5.17%, -1.03)
use-rev-num: 17.493725 (-12.30%, -2.45)
this-changesets: 15.919466 (-20.19%, -4.03)
syntax: glob
*.elc
*.tmp
*.orig
*.rej
*~
*.mergebackup
*.o
*.so
*.dll
*.exe
*.pyd
*.pyc
*.pyo
*$py.class
*.swp
*.prof
*.zip
\#*\#
.\#*
result/
tests/artifacts/cache/big-file-churn.hg
tests/.coverage*
tests/.testtimes*
# the file is written in the CWD when run-tests is run.
.testtimes
tests/.hypothesis
tests/hypothesis-generated
tests/annotated
tests/exceptions
tests/python3
tests/*.err
tests/htmlcov
build
contrib/chg/chg
contrib/hgsh/hgsh
contrib/vagrant/.vagrant
contrib/merge-lists/target/
dist
packages
doc/common.txt
doc/*.[0-9]
doc/*.[0-9].txt
doc/*.[0-9].gendoc.txt
doc/*.[0-9].{x,ht}ml
MANIFEST
MANIFEST.in
patches
mercurial/__modulepolicy__.py
mercurial/__version__.py
mercurial/hgpythonlib.h
mercurial.egg-info
.DS_Store
tags
cscope.*
.vscode/*
.idea/*
.asv/*
.pytype/*
.mypy_cache
i18n/hg.pot
locale/*/LC_MESSAGES/hg.mo
hgext/__index__.py
rust/target/
rust/*/target/
# Generated wheels
wheelhouse/
syntax: rootglob
# See Profiling in rust/README.rst
.cargo/config
syntax: regexp
^\.pc/
^\.(pydev)?project
# hackable windows distribution additions
^hg-python
^hg.py$