http/tests/devtools/sources/debugger/debugger-disable-enable.js timeout

Suspect this is also related to the devtools frontend roll in
https://chromium-review.googlesource.com/c/chromium/src/+/2038189

Sample failure at
https://ci.chromium.org/p/chromium/builders/ci/WebKit%20Linux%20MSAN/4217

TBR=tvanderlippe@chromium.org

Bug: 1049641
Change-Id: Ic6d75cb6e3644c5fbf2fcbb0e955120ae442e3c3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2042796Reviewed-by: Robert Flack <flackr@chromium.org>
Commit-Queue: Robert Flack <flackr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#739159}

third_party/blink/web_tests/TestExpectations

@@ -2185,6 +2185,7 @@ crbug.com/1049599 [ Linux ] virtual/threaded-prefer-compositing/fast/scrolling/e
 crbug.com/1049641 [ Debug ] http/tests/devtools/sources/debugger/js-with-inline-stylesheets.js [ Pass Failure ]
 crbug.com/1049641 [ Debug ] http/tests/devtools/sources/debugger-breakpoints/set-breakpoint.js [ Pass Failure ]
 crbug.com/1049641 [ Debug ] http/tests/devtools/sources/debugger-breakpoints/set-conditional-breakpoint.js [ Pass Failure ]
+crbug.com/1049641 http/tests/devtools/sources/debugger/debugger-disable-enable.js [ Pass Timeout ]
 
 # Sheriff 2019-08-19
 crbug.com/626703 [ Win7 ] external/wpt/xhr/responsexml-document-properties.htm [ Failure ]