Revert "Update third_party/devtools-frontend 70f122128c..8bb84e5801"

This reverts commit eb349bc7.

Reason for revert: This cl is likely causing this https://ci.chromium.org/p/chromium/builders/ci/linux-trusty-rel/4085 deterministic failure. 

Original change's description:
> Update third_party/devtools-frontend 70f122128c..8bb84e5801
> 
> https://chromium.googlesource.com/devtools/devtools-frontend/+log/70f122128c..8bb84e5801
> 
> TBR=aerotwist@chromium.org
> 
> Change-Id: Id2370e489efc7024b916b328f7e8f46e9f314bec
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1886410
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Commit-Queue: Yang Guo <yangguo@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#710264}

TBR=yangguo@chromium.org,aerotwist@chromium.org

Change-Id: I6af7c5ef3d7142a8e1bf9eb39fb5ae55a00410f2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1886334Reviewed-by: Kamila Hasanbega <hkamila@chromium.org>
Commit-Queue: Kamila Hasanbega <hkamila@chromium.org>
Cr-Commit-Position: refs/heads/master@{#710297}

DEPS

@@ -243,7 +243,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling devtools-frontend
   # and whatever else without interference from each other.
-  'devtools_frontend_revision': '8bb84e58013a42efc9457b469b3b1a845ebaa5c7',
+  'devtools_frontend_revision': '70f122128c1413406b1eb8907449684f164d156f',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling libprotobuf-mutator
   # and whatever else without interference from each other.