Unskip blink_perf.css stories

Now that the underlying issues are fixed, let's enable these tests
again.

BUG=983728, 983608, 1042644
R=futhark@chromium.org

Change-Id: Ide367e47806995c15c185f95f03b21524c1b7058
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2002586Reviewed-by: Mikhail Khokhlov <khokhlov@google.com>
Reviewed-by: Caleb Rouleau <crouleau@chromium.org>
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Commit-Queue: Caleb Rouleau <crouleau@chromium.org>
Cr-Commit-Position: refs/heads/master@{#732985}

tools/perf/expectations.config

@@ -66,15 +66,6 @@ crbug.com/1036446 [ mac-10.12 ] blink_perf.canvas/draw-static-canvas-2d-to-hw-ac
 
 # Benchmark: blink_perf.css
 crbug.com/891878 [ android-nexus-5x android-webview ] blink_perf.css/CustomPropertiesVarAlias.html [ Skip ]
-crbug.com/983728 blink_perf.css/ClassDescendantSelector.html [ Skip ]
-crbug.com/983728 blink_perf.css/ClassInvalidation.html [ Skip ]
-crbug.com/983728 blink_perf.css/CustomPropertiesCascade.html [ Skip ]
-crbug.com/983728 blink_perf.css/CustomPropertiesNonRootInheritance.html [ Skip ]
-crbug.com/983728 blink_perf.css/CustomPropertiesRootInheritance.html [ Skip ]
-crbug.com/983728 blink_perf.css/CustomPropertiesVarAlias.html [ Skip ]
-crbug.com/983728 blink_perf.css/FocusUpdate.html [ Skip ]
-crbug.com/983728 blink_perf.css/PseudoClassSelectors.html [ Skip ]
-crbug.com/983728 blink_perf.css/SelectorCountScaling.html [ Skip ]
 
 # Benchmark: blink_perf.events
 crbug.com/986423 [ android-nexus-5x android-webview ] blink_perf.events/EventsDispatchingInDeeplyNestedV0ShadowTrees.html [ Skip ]