Unflake inspector/sources/debugger/async-callstack-in-console.html

BUG=392531
TBR=yurys
NOTRY=true

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=177807

Review URL: https://codereview.chromium.org/378293006

git-svn-id: svn://svn.chromium.org/blink/trunk@177848 bbb929c8-8fbe-4397-9dbb-9b2b20218538