This reverts commit 602076dc.

Reason for revert:

It fails on input 0xe2 0x9c 0x94 which is a utf-8 heavy check mark. Problem is that CheckCallAndFilter is processing output byte by byte, so trying to decode only one of utf-8 bytes in sequence will always fail.

Original change's description:
> depot_tools: Make gclient_utils Python 3 compatible.
> 
> Bug: 984182
> Change-Id: Ifb93466dcb7541f46c31c9b298049c425dd150d6
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1715472
> Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
> Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>

TBR=tandrii@chromium.org,ehmaldonado@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 984182
Change-Id: Ieae421acc430a031621db3329223c1da85506e55
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1724730Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>