Eliminate NormalizeDir. Eliminate gratuitous stat/access calls per dir.

Eliminate NormalizeDir. Eliminate gratuitous stat/access calls per dir.

Normalized directory names offer protection against looped directory trees
but cost enormous numbers of system calls (stat per file in the hierarchy).
Also, cache file directory name contents are validated each time the
directory is modified, don't re-validate every time the cache file is loaded
with an access and stat call.