tests/test-pushvars.t

treemanifest: stop storing full path for each item in manifest._lazydirs

This information is obtainable, if needed, based on the lazydirs key (which is
the entry name) and the manifest's `dir()` method.

### Performance

This is actually both a memory and a performance improvement, but it's likely to
be a very small one in most situations. In the pathological repo I've been using
for testing other performance work I've done recently, this reduced the time for
a rebase operation (rebasing two commits across a public-phase change that
touches a sibling of one of my tracked directories where the common parent is
massive (>>10k entries)):

#### Before

```
  Time (mean ± σ):      4.059 s ±  0.121 s    [User: 0.9 ms, System: 0.6 ms]
  Range (min … max):    3.941 s …  4.352 s    10 runs
```

#### After

```
  Time (mean ± σ):      3.707 s ±  0.060 s    [User: 0.8 ms, System: 0.8 ms]
  Range (min … max):    3.648 s …  3.818 s    10 runs
```

Differential Revision: https://phab.mercurial-scm.org/D9553

Setup

  $ PYTHONPATH=$TESTDIR/..:$PYTHONPATH
  $ export PYTHONPATH

  $ cat > $TESTTMP/pretxnchangegroup.sh << EOF
  > #!/bin/sh
  > env | egrep "^HG_USERVAR_(DEBUG|BYPASS_REVIEW)" | sort
  > exit 0
  > EOF
  $ cat >> $HGRCPATH << EOF
  > [hooks]
  > pretxnchangegroup = sh $TESTTMP/pretxnchangegroup.sh
  > EOF

  $ hg init repo
  $ hg clone -q repo child
  $ cd child

Test pushing vars to repo with pushvars.server not set

  $ echo b > a
  $ hg commit -Aqm a
  $ hg push --pushvars "DEBUG=1" --pushvars "BYPASS_REVIEW=true"
  pushing to $TESTTMP/repo
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files

Setting pushvars.sever = true and then pushing.

  $ echo [push] >> $HGRCPATH
  $ echo "pushvars.server = true" >> $HGRCPATH
  $ echo b >> a
  $ hg commit -Aqm a
  $ hg push --pushvars "DEBUG=1" --pushvars "BYPASS_REVIEW=true"
  pushing to $TESTTMP/repo
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  HG_USERVAR_BYPASS_REVIEW=true
  HG_USERVAR_DEBUG=1
  added 1 changesets with 1 changes to 1 files

Test pushing var with empty right-hand side

  $ echo b >> a
  $ hg commit -Aqm a
  $ hg push --pushvars "DEBUG="
  pushing to $TESTTMP/repo
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  HG_USERVAR_DEBUG=
  added 1 changesets with 1 changes to 1 files

Test pushing bad vars

  $ echo b >> a
  $ hg commit -Aqm b
  $ hg push --pushvars "DEBUG"
  pushing to $TESTTMP/repo
  searching for changes
  abort: unable to parse variable 'DEBUG', should follow 'KEY=VALUE' or 'KEY=' format
  [255]