[zip] Add UnzipOptions::encoding

Added tests:
ZipTest.UnzipSjis
ZipTest.UnzipSjisAsUtf8

BUG=chromium:1287893, chromium:953256
TEST=autoninja -C out/Default zlib_unittests && out/Default/zlib_unittests

Change-Id: Ibdf79b80c76362a768af7cfa134267ef400c30aa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3478934


Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Commit-Queue: François Degros <fdegros@chromium.org>
Cr-Commit-Position: refs/heads/main@{#973605}
NOKEYCHECK=True
GitOrigin-RevId: e1fbfd300044b4b029a3a3faee660ca93f1bcd42