[reland] SegmentedString::push() should always push a char in front

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 3795 matching lines @@
             'html/HTMLImageElementTest.cpp',
             'html/HTMLInputElementTest.cpp',
             'html/HTMLLinkElementSizesAttributeTest.cpp',
             'html/HTMLSelectElementTest.cpp',
             'html/HTMLTableRowElementTest.cpp',
             'html/HTMLTextFormControlElementTest.cpp',
             'html/LinkRelAttributeTest.cpp',
             'html/TimeRangesTest.cpp',
             'html/canvas/CanvasFontCacheTest.cpp',
             'html/forms/FileInputTypeTest.cpp',
+            'html/parser/HTMLEntityParserTest.cpp',
             'html/parser/HTMLParserThreadTest.cpp',
             'html/parser/HTMLPreloadScannerTest.cpp',
             'html/parser/HTMLResourcePreloaderTest.cpp',
             'html/parser/HTMLSrcsetParserTest.cpp',
             'html/shadow/MediaControlsTest.cpp',
             'html/track/vtt/BufferedLineReaderTest.cpp',
             'html/track/vtt/VTTScannerTest.cpp',
             'input/EventHandlerTest.cpp',
             'layout/ImageQualityControllerTest.cpp',
             'layout/LayoutBlockTest.cpp',
@@ skipping 29 matching lines @@
             'style/OutlineValueTest.cpp',
             'style/SVGComputedStyleTest.cpp',
             'svg/UnsafeSVGAttributeSanitizationTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'timing/MemoryInfoTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }