[ macOS Debug WK2 ] ASSERT call in RenderVTTCue.cpp causing flaky cra…

…sh (media/modern-media-controls/tracks-support/text-track-selected-via-media-api.html)

https://bugs.webkit.org/show_bug.cgi?id=259544
rdar://112951082

Reviewed by Jer Noble.

Remove two unneeded asserts. Both checked a condition that is commonly encountered and which
is not dangerous or harmful.

* LayoutTests/platform/mac-wk2/TestExpectations: Unskip test.

* Source/WebCore/rendering/RenderVTTCue.cpp:
(WebCore::RenderVTTCue::repositionCueSnapToLinesSet): Remove assert.
(WebCore::RenderVTTCue::repositionGenericCue): Ditto.

Canonical link: https://commits.webkit.org/266513@main

LayoutTests/platform/mac-wk2/TestExpectations

@@ -1826,8 +1826,6 @@ webkit.org/b/259496 [ x86_64 ] imported/w3c/web-platform-tests/webcodecs/tempora
 
 webkit.org/b/238033 imported/w3c/web-platform-tests/css/css-contain/content-visibility/content-visibility-050.html [ Pass Failure ]
 
-webkit.org/b/259544 [ Debug ] media/modern-media-controls/tracks-support/text-track-selected-via-media-api.html [ Pass Crash ]
-
 webkit.org/b/259183 fast/attachment/mac/wide-attachment-image-controls-basic.html [ Pass Failure ]
 
 webkit.org/b/259699 media/media-source/media-source-duplicate-seeked.html [ Pass Failure ]

Source/WebCore/rendering/RenderVTTCue.cpp

@@ -346,7 +346,6 @@ void RenderVTTCue::repositionCueSnapToLinesSet()
     if (!initializeLayoutParameters(step, position))
         return;
 
-    ASSERT(firstChild());
     if (!firstChild())
         return;
 
@@ -377,7 +376,6 @@ void RenderVTTCue::repositionCueSnapToLinesSet()
 
 void RenderVTTCue::repositionGenericCue()
 {
-    ASSERT(firstChild());
     if (!firstChild())
         return;