Revert "Mark two virtual/android tests as Slow for causing flaky timeouts"

This reverts commit 50fdef03.

Reason for revert: The root cause of the slowness is elsewhere, and the
tests will be removed from the configurations they're timing out on.

Original change's description:
> Mark two virtual/android tests as Slow for causing flaky timeouts
> 
> virtual/android/url-bar/bottom-fixed-adjusted-when-showing-url-bar.html
> and virtual/android/fullscreen/video-scrolled-iframe.html are causing
> flaky timeouts.
> 
> TBR=nator@chromiun.org
> 
> Bug: 1049138
> No-Try: true
> Change-Id: If30b1c39d7b73354e782458c924708bc820934c7
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2039143
> Reviewed-by: Austin Eng <enga@chromium.org>
> Commit-Queue: Austin Eng <enga@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#738592}

TBR=nator@chromium.org,enga@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 1049138, 1049138
Change-Id: I4d3135d309c1bf4ca1fc7531fa970d80468d7c76
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2042321Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Austin Eng <enga@chromium.org>
Cr-Commit-Position: refs/heads/master@{#739175}

third_party/blink/web_tests/SlowTests

@@ -677,6 +677,3 @@ crbug.com/1048204 external/wpt/selection/idlharness.window.html [ Slow ]
 # Reaching the stack size limit makes for a consistently slow test with
 # occasional timeouts on Win7
 crbug.com/937546 [ Win7 ] http/tests/security/xss-DENIED-cross-origin-stack-overflow.html [ Slow ]
-
-crbug.com/1049138 virtual/android/url-bar/bottom-fixed-adjusted-when-showing-url-bar.html [ Slow ]
-crbug.com/1049138 virtual/android/fullscreen/video-scrolled-iframe.html [ Slow ]