[DevTools] Reenable async stepping tests after roll

Bug: 1000475
TBR=alph@chromium.org

Change-Id: I9a9c3abcf731de3b76bcd701214e164790821f4c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1804676Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#696606}

third_party/blink/web_tests/TestExpectations

@@ -2354,12 +2354,6 @@ crbug.com/688613 external/wpt/mediacapture-streams/MediaStreamTrack-MediaElement
 crbug.com/688613 virtual/feature-policy-permissions/external/wpt/mediacapture-streams/MediaStreamTrack-MediaElement-disabled-audio-is-silence.https.html [ Skip ]
 crbug.com/688613 virtual/audio-service/external/wpt/mediacapture-streams/MediaStreamTrack-MediaElement-disabled-audio-is-silence.https.html [ Skip ]
 
-# Disabled until v8 roll, which brings new async stepping mechanism.
-crbug.com/1000475 inspector-protocol/debugger/message-channel-async-stack.js [ Skip ]
-crbug.com/1000475 inspector-protocol/worker/worker-constructor-async-stacks.js [ Skip ]
-crbug.com/1000475 inspector-protocol/worker/worker-on-message-async-stacks.js [ Skip ]
-crbug.com/1000475 inspector-protocol/worker/worker-post-message-async-stacks.js [ Skip ]
-
 crbug.com/766135 fast/dom/Window/redirect-with-timer.html [ Timeout Pass ]
 
 # Ref tests that needs investigation.