Rebaseline virtual/.../overflow-compositing-descendant.html on Win7

Remove the extra baseline that was produced when the test flakily
failed. The flakiness has been fixed by another CL.

TBR=clamy@chromium.org

Bug: 1084448
Change-Id: Ic7d01deeea6d0ca3511f572808d2e16ec6237550
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2210622Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#770737}

third_party/blink/web_tests/TestExpectations

@@ -5896,6 +5896,3 @@ crbug.com/1084509 [ Win ] fast/forms/select/listbox-appearance-basic.html [ Pass
 crbug.com/1011811 http/tests/devtools/network/network-xhr-data-received-async-response-type-blob.js [ Pass Failure ]
 crbug.com/1011811 http/tests/devtools/network/download.js [ Pass Failure ]
 crbug.com/1011811 http/tests/devtools/sxg/sxg-disable-cache.js [ Pass Failure ]
-
-# Sheriff 2020-05-20
-crbug.com/1084448 [ Win ] compositing/overflow/overflow-compositing-descendant.html [ Pass Failure ]