Update unrar to 5.7.3

This change updates unrar to 5.7.3 and reconciles the old patch file in
the few places where we have merge conflicts.

Bug: 936112
Change-Id: I34da1c92e232167fbfe088730f111c3670332273
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1591871
Reviewed-by: Varun Khaneja <vakh@chromium.org>
Commit-Queue: Daniel Rubery <drubery@chromium.org>
Cr-Commit-Position: refs/heads/master@{#660571}
51 files changed