Revert "libwebp: update to 1.0.2"

This reverts commit 7a1729743378a9b0521ac14a9088ce1148754497.

Reason for revert: Suspect compile failure on Win32-rel
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/win32-rel/10047

Original change's description:
> libwebp: update to 1.0.2
> 
> minor encoder speedups and roll up to pick up local fuzzer cherry-pick
> 
> Bug: 922319
> Change-Id: I2c8be4423aab86c406c3d4d2848950178337da3c
> Reviewed-on: https://chromium-review.googlesource.com/c/1412021
> Reviewed-by: Urvang Joshi <urvang@chromium.org>
> Commit-Queue: James Zern <jzern@google.com>
> Cr-Commit-Position: refs/heads/master@{#625099}

TBR=jzern@google.com,urvang@chromium.org

Change-Id: I8bb8f22990696269d18f35a95aa611ab4a3efeba
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 922319
Reviewed-on: https://chromium-review.googlesource.com/c/1428629
Reviewed-by: Takashi Sakamoto <tasak@google.com>
Commit-Queue: Takashi Sakamoto <tasak@google.com>
Cr-Commit-Position: refs/heads/master@{#625107}
23 files changed