Enable `as` based priorities for <link rel=preload>

Source/core/core.gypi

 {
     'includes': [
         'core_generated.gypi',
     ],
     'variables': {
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/KeyframeEffect.idl',
             'animation/EffectModel.idl',
             'animation/AnimationEffectReadOnly.idl',
@@ skipping 3866 matching lines @@
             'layout/LayoutTableCellTest.cpp',
             'layout/LayoutTableRowTest.cpp',
             'layout/LayoutTestHelper.cpp',
             'layout/LayoutTestHelper.h',
             'layout/LayoutThemeTest.cpp',
             'layout/MultiColumnFragmentainerGroupTest.cpp',
             'layout/OverflowModelTest.cpp',
             'layout/shapes/BoxShapeTest.cpp',
             'loader/FrameFetchContextTest.cpp',
             'loader/LinkHeaderTest.cpp',
+            'loader/LinkLoaderTest.cpp',
             'loader/MixedContentCheckerTest.cpp',
             'page/ContextMenuControllerTest.cpp',
             'page/NetworkStateNotifierTest.cpp',
             'page/PrintContextTest.cpp',
             'page/scrolling/ScrollStateTest.cpp',
             'paint/DisplayItemListPaintTest.cpp',
             'paint/LayerClipRecorderTest.cpp',
             'paint/LayoutObjectDrawingRecorderTest.cpp',
             'paint/TextPainterTest.cpp',
             'streams/ReadableStreamReaderTest.cpp',
             'streams/ReadableStreamTest.cpp',
             'style/ComputedStyleTest.cpp',
             'style/OutlineValueTest.cpp',
             'style/SVGComputedStyleTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'timing/MemoryInfoTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }