Merge branch 'jc/diff-cached-fsmonitor-fix' into next

The optimization based on fsmonitor in the "diff --cached"
codepath is resurrected with the "fake-lstat" introduced earlier.

* jc/diff-cached-fsmonitor-fix:
  diff-lib: fix check_removed() when fsmonitor is active

diff-lib.c

@@ -38,7 +38,13 @@
  */
 static int check_removed(const struct cache_entry *ce, struct stat *st)
 {
- if (lstat(ce->name, st) < 0) {
+ int stat_err;
+
+ if (!(ce->ce_flags & CE_FSMONITOR_VALID))
+ stat_err = lstat(ce->name, st);
+ else
+ stat_err = fake_lstat(ce, st);
+ if (stat_err < 0) {
  if (!is_missing_file_error(errno))
  return -1;
  return 1;