tests/test-1102.t

revlog: speed up prefix matching against nodes

The radix tree already contains all the information we need to
determine whether a short string is an unambiguous node identifier.
We now make use of this information.

In a kernel tree, this improves the performance of
"hg log -q -r24bf01de75" from 0.27 seconds to 0.06.

  $ rm -rf a
  $ hg init a
  $ cd a
  $ echo a > a
  $ hg ci -Am0
  adding a
  $ hg tag t1 # 1
  $ hg tag --remove t1 # 2

  $ hg co 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg tag -f -r0 t1
  $ hg tags
  tip                                3:a49829c4fc11
  t1                                 0:f7b1eb17ad24