Change downsample-quality.html test expectations

Changed downsample-quality.html test expectations
because of Step "blink_web_tests" failing on builder
"Linux Tests (dbg)(1)"

TBR: junov@chromium.org

No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1113127
Change-Id: I45d5547ec7800e51126ee73487952aedada10a00
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2336091Reviewed-by: Aya Elsayed <ayaelattar@chromium.org>
Commit-Queue: Aya Elsayed <ayaelattar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#794990}

third_party/blink/web_tests/TestExpectations

@@ -6858,3 +6858,4 @@ crbug.com/1112771 external/wpt/css/css-grid/grid-definition/grid-inline-template
 
 # Sheriff 2020-08-05
 crbug.com/1113050 fast/borders/border-radius-mask-video-ratio.html [ Pass Failure ]
+crbug.com/1113127 fast/canvas/downsample-quality.html [ Pass Failure ]
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