Fix flakiness of imported/web-platform-tests/html/syntax/parsing/html5lib_testsNN.html.

LayoutTests/TestExpectations

 # We tests under paint/invalidation/spv2 as --enable-slimming-paint-v2 physical suite. 
 crbug.com/524134 virtual/spv2/paint/invalidation/spv2 [ Skip ]
 
 # TODO(wangxianzhu): Triage the failures
 crbug.com/524134 virtual/spv2/compositing/repaint/opacity-between-absolute.html [ ImageOnlyFailure ]
 crbug.com/524134 virtual/spv2/compositing/repaint/opacity-between-absolute2.html [ ImageOnlyFailure ]
 crbug.com/524134 virtual/spv2/fast/repaint/absolute-position-changed.html [ Failure ImageOnlyFailure ]
 crbug.com/524134 virtual/spv2/fast/repaint/align-self-change-keeping-geometry-grid.html [ Failure ]
 crbug.com/524134 virtual/spv2/fast/repaint/block-selection-gap-in-composited-layer.html [ ImageOnlyFailure ]
 crbug.com/524134 virtual/spv2/fast/repaint/clip-path-constant-repaint.html [ Failure ]
@@ skipping 387 matching lines @@
 crbug.com/526920 imported/web-platform-tests/html/semantics/embedded-content/media-elements/location-of-the-media-resource/currentSrc.html [ Failure ]
 crbug.com/520835 imported/web-platform-tests/html/semantics/forms/attributes-common-to-form-controls/formAction_document_address.html [ Failure ]
 crbug.com/520835 imported/web-platform-tests/html/semantics/forms/attributes-common-to-form-controls/formaction.html [ Failure ]
 # script-for-event.html: We can't check in failure results because we also have
 # script-for-event.xhtml.
 crbug.com/520844 imported/web-platform-tests/html/semantics/scripting-1/the-script-element/script-for-event.html [ Failure ]
 crbug.com/525889 imported/web-platform-tests/html/webappapis/scripting/processing-model-2/compile-error-in-setInterval.html [ Failure ]
 crbug.com/525889 imported/web-platform-tests/html/webappapis/scripting/processing-model-2/compile-error-in-setTimeout.html [ Failure ]
 crbug.com/525889 imported/web-platform-tests/html/webappapis/scripting/processing-model-2/runtime-error-in-setInterval.html [ Failure ]
 crbug.com/525889 imported/web-platform-tests/html/webappapis/scripting/processing-model-2/runtime-error-in-setTimeout.html [ Failure ]
-crbug.com/527262 imported/web-platform-tests/html/syntax/parsing/html5lib_tests19.html [ Failure Pass Slow ]
-crbug.com/527262 imported/web-platform-tests/html/syntax/parsing/html5lib_tests2.html [ Failure Pass Slow ]
 
 crbug.com/505364 imported/web-platform-tests/shadow-dom/elements-and-dom-objects/extensions-to-element-interface/methods/elements-001.html [ Failure ]
 crbug.com/505364 imported/web-platform-tests/shadow-dom/events/event-dispatch/test-003.html [ Failure ]
 crbug.com/505364 imported/web-platform-tests/shadow-dom/events/retargeting-relatedtarget/test-003.html [ Failure ]
 crbug.com/505364 imported/web-platform-tests/shadow-dom/html-elements-and-their-shadow-trees/test-001.html [ Failure Crash ]
 crbug.com/505364 imported/web-platform-tests/shadow-dom/html-elements-and-their-shadow-trees/test-002.html [ Failure ]
 crbug.com/505364 imported/web-platform-tests/shadow-dom/html-elements-and-their-shadow-trees/test-003.html [ Failure ]
 crbug.com/505364 imported/web-platform-tests/shadow-dom/html-elements-in-shadow-trees/html-forms/test-003.html [ Failure ]
 crbug.com/505364 imported/web-platform-tests/shadow-dom/shadow-trees/custom-pseudo-elements/test-001.html [ Failure ]
 crbug.com/505364 imported/web-platform-tests/shadow-dom/styles/css-variables/test-001.html [ Failure ]
@@ skipping 1205 matching lines @@
 
 crbug.com/525296 fast/css/font-load-while-styleresolver-missing.html [ Crash ImageOnlyFailure Pass ]
 
 crbug.com/525299 [ MountainLion Mavericks XP Win10 ] http/tests/security/redirect-BLOCKED-to-localURL.html [ Failure Pass ]
 
 crbug.com/525903 inspector/sources/debugger-ui/watch-expressions-preserve-expansion.html [ Failure Pass ]
 
 crbug.com/457273 [ Mac ] http/tests/websocket/close.html [ Pass Timeout ]
 
 crbug.com/527009 fast/dom/plugin-attributes-enumeration.html [ NeedsManualRebaseline ]