tests/test-remotefilelog-bad-configs.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

#require no-windows

  $ . "$TESTDIR/remotefilelog-library.sh"

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [remotefilelog]
  > server=True
  > EOF
  $ echo x > x
  $ echo y > y
  $ echo z > z
  $ hg commit -qAm xy

  $ cd ..

  $ hgcloneshallow ssh://user@dummy/master shallow -q
  3 files fetched over 1 fetches - (3 misses, 0.00% hit ratio) over *s (glob)
  $ cd shallow

Verify error message when noc achepath specified
  $ hg up -q null
  $ cp $HGRCPATH $HGRCPATH.bak
  $ grep -v cachepath < $HGRCPATH.bak > tmp
  $ mv tmp $HGRCPATH
  $ hg up tip
  abort: could not find config option remotefilelog.cachepath
  [255]
  $ mv $HGRCPATH.bak $HGRCPATH

Verify error message when no fallback specified

  $ hg up -q null
  $ rm .hg/hgrc
  $ clearcache
  $ hg up tip
  3 files fetched over 1 fetches - (3 misses, 0.00% hit ratio) over *s (glob)
  abort: no remotefilelog server configured - is your .hg/hgrc trusted?
  [255]