shrink: delete extension preventing further refactoring (BC)

Reordering can be done by setting bundle.reorder to true and doing a
clone --pull.

tests/test-contrib.t

@@ -103,34 +103,6 b' Compare repos:'
   no changes found
   [1]
 
-
-#if hardlink
-
-Test shrink-revlog:
-  $ cd repo-a
-  $ hg --config extensions.shrink="$CONTRIBDIR/shrink-revlog.py" shrink
-  shrinking $TESTTMP/repo-a/.hg/store/00manifest.i (glob)
-  reading revs
-  sorting revs
-  writing revs
-  old file size:          324 bytes (   0.0 MiB)
-  new file size:          324 bytes (   0.0 MiB)
-  shrinkage: 0.0% (1.0x)
-  note: old revlog saved in:
-    $TESTTMP/repo-a/.hg/store/00manifest.i.old (glob)
-    $TESTTMP/repo-a/.hg/store/00manifest.d.old (glob)
-  (You can delete those files when you are satisfied that your
-  repository is still sane.  Running 'hg verify' is strongly recommended.)
-  $ hg verify
-  checking changesets
-  checking manifests
-  crosschecking files in changesets and manifests
-  checking files
-  1 files, 3 changesets, 3 total revisions
-  $ cd ..
-
-#endif
-
 Test simplemerge command:
 
   $ cp "$CONTRIBDIR/simplemerge" .