[Sheriff] Mark storage/indexeddb/index-population.html as flaky-TIMEOUT on Windows

TBR=dmurph@chromium.org

Bug: 925325
Change-Id: I7cbc37cbcc0134a6204781e66b137f4b537832c1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1879147Reviewed-by: Stephen McGruer <smcgruer@chromium.org>
Commit-Queue: Stephen McGruer <smcgruer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709130}

third_party/blink/web_tests/TestExpectations

@@ -5718,6 +5718,7 @@ crbug.com/1016804 external/wpt/css/css-grid/layout-algorithm/grid-flex-track-int
 
 # Sheriff 2019-10-24
 crbug.com/1017626 [ Linux ] external/wpt/compat/idlharness.window.html [ Pass Timeout ]
+crbug.com/925325 [ Win ] storage/indexeddb/index-population.html [ Pass Timeout ]
 
 # DevTools Security Panel (disabled temporarily as part of workflow)
 crbug.com/1008218 http/tests/devtools/security/security-state-comparator.js [ Failure ]