Expect timeout for flaky external/wpt/mimesniff/mime-types/parsing.any.worker.html

TBR=robertma@chromium.org

Bug: 793792
Change-Id: I213dc2cee10082216585195392273db767804929
Reviewed-on: https://chromium-review.googlesource.com/819210
Commit-Queue: Maxim Kolosovskiy <kolos@chromium.org>
Reviewed-by: Maxim Kolosovskiy <kolos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#523087}

third_party/WebKit/LayoutTests/TestExpectations

@@ -1373,6 +1373,8 @@ crbug.com/492664 [ Mac ] external/wpt/css/css-writing-modes/sizing-orthog-htb-in
 crbug.com/492664 [ Mac ] external/wpt/css/css-writing-modes/text-baseline-vrl-006.xht [ Failure ]
 crbug.com/492664 [ Mac ] external/wpt/css/css-writing-modes/text-baseline-vlr-007.xht [ Failure ]
 
+crbug.com/793792 [ Linux ] external/wpt/mimesniff/mime-types/parsing.any.worker.html [ Pass Timeout ]
+
 crbug.com/498845 [ Win ] fast/multicol/vertical-rl/float-content-break.html [ Failure ]
 crbug.com/443615 [ Linux Win ] external/wpt/css/css-shapes/shape-outside/supported-shapes/circle/shape-outside-circle-027.html [ Failure ]