Merge branch 'ds/more-index-cleanups'

Cleaning various codepaths up.

* ds/more-index-cleanups:
  t1092: test interesting sparse-checkout scenarios
  test-lib: test_region looks for trace2 regions
  sparse-checkout: load sparse-checkout patterns
  name-hash: use trace2 regions for init
  repository: add repo reference to index_state
  fsmonitor: de-duplicate BUG()s around dirty bits
  cache-tree: extract subtree_pos()
  cache-tree: simplify verify_cache() prototype
  cache-tree: clean up cache_tree_update()

diff --cc cache.h
Simple merge

diff --cc sequencer.c
Simple merge

diff --cc t/test-lib-functions.sh
Simple merge