Merge branch 'ds/fetch-pull-with-sparse-index'

Merge branch 'ds/fetch-pull-with-sparse-index'

"git fetch" and "git pull" are now declared sparse-index clean.
Also "git ls-files" learns the "--sparse" option to help debugging.

* ds/fetch-pull-with-sparse-index:
  test-read-cache: remove --table, --expand options
  t1091/t3705: remove 'test-tool read-cache --table'
  t1092: replace 'read-cache --table' with 'ls-files --sparse'
  ls-files: add --sparse option
  fetch/pull: use the sparse index