LibWeb: Use available space to resolve table cells width

It is not possible to use width of containing block to resolve
cells width because by the time compute_table_measures() is
called row width is not known yet.

Userland/Libraries/LibWeb/Layout/TableFormattingContext.h

@@ -28,6 +28,8 @@ private:
 
     CSSPixels m_automatic_content_height { 0 };
 
+    Optional<AvailableSpace> m_available_space;
+
     struct Column {
         CSSPixels left_offset { 0 };
         CSSPixels min_width { 0 };