CheckDirMetadataFormat executes dirmd on all applicable files. When
running "git cl presubmit --all" that ends up being ~7,500 files and
the command line that is generated is ~500,000 characters. Windows does
not like that.

This change breaks up the check into multiple invocations of dirmd in
order to avoid these limits. This is important because running all
presubmits is the only way to systematically find bugs, and avoid being
surprised by them when submitting a change.

Bug: 1309977
Change-Id: I24fbc340cdb975dbe7f6a2132e516d6f7e2f9165
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3554633Reviewed-by: Robbie Iannucci <iannucci@chromium.org>
Reviewed-by: Josip Sokcevic <sokcevic@google.com>
Commit-Queue: Bruce Dawson <brucedawson@chromium.org>