Use continues to reduce the amount of nesting in a loop. At the same
time, give the variable involved better names.

Bug: 1097674
Change-Id: I105ed4a99da783fb235e304bbad4edd1f8a38889
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2298659Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>