Make compression_utils buildable also without Chromium.

Starting from https://chromium-review.googlesource.com/c/chromium/src/+/2171416
the target //tools/android/md5sum:md5sum_bin started to depend on
//third_party/zlib/google:compression_utils.

The standalone WebRTC build (without Chromium) depends on
//tools/android/md5sum:md5sum_bin, so this CL moves compression_utils out
of the "if (build_with_chromium)" block.

Bug: None
Change-Id: Ib9e12109398b88aad7750596cc72baf49b19658e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2193776


Commit-Queue: Mirko Bonadei <mbonadei@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#767692}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: c97b5d2a57523232407705c0a1b64cf8fa3b5910