Remove entry for realtime-conv.html timeout

https://wpt.fyi/results/webaudio/the-audio-api/the-convolvernode-interface?label=master&label=experimental
doesn't show any test failures so let's try removing the entry from
TestExpectations.  Local runs on a macbook show no timeouts either.

Bug: 989036
Change-Id: I7ca70277f7ca9578931686967a7199e3e4e5148c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1743076Reviewed-by: Hongchan Choi <hongchan@chromium.org>
Commit-Queue: Raymond Toy <rtoy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#685321}

third_party/blink/web_tests/TestExpectations

@@ -3358,7 +3358,6 @@ crbug.com/626703 [ Mac10.12 ] external/wpt/html/semantics/embedded-content/media
 crbug.com/626703 [ Mac10.12 ] external/wpt/mediacapture-fromelement/ended.html [ Timeout ]
 crbug.com/626703 [ Mac10.12 ] external/wpt/html/semantics/embedded-content/media-elements/track/track-element/track-cues-pause-on-exit.html [ Timeout ]
 crbug.com/626703 [ Mac10.10 ] external/wpt/workers/data-url-shared.html [ Crash ]
-crbug.com/626703 [ Mac10.12 ] external/wpt/webaudio/the-audio-api/the-convolvernode-interface/realtime-conv.html [ Timeout ]
 crbug.com/626703 [ Win7 ] external/wpt/pointerevents/pointerevent_touch-action-svg-none-test_touch.html [ Timeout ]
 crbug.com/626703 [ Win7 ] external/wpt/pointerevents/extension/pointerevent_touch-action-pan-right-css_touch.html [ Timeout ]
 crbug.com/626703 [ Mac10.11 ] external/wpt/shape-detection/detection-security-test.https.html [ Timeout ]