Issue #3204929 by longwave, donquixote, andypost: Html::load() inconsistent space removal with old libxml2 versions

(cherry picked from commit d8d13be9c8)

core/lib/Drupal/Component/Utility/Html.php

@@ -286,7 +286,7 @@ EOD;
 
     $dom = new \DOMDocument();
     // Ignore warnings during HTML soup loading.
-    @$dom->loadHTML($document);
+    @$dom->loadHTML($document, LIBXML_NOBLANKS);
 
     return $dom;
   }

core/misc/cspell/dictionary.txt

@@ -886,6 +886,7 @@ nmsgstr
 nntp
 noaccess
 noadd
+noblanks
 nocache
 nocase
 nocdata

core/tests/Drupal/KernelTests/AssertContentTrait.php

@@ -125,7 +125,7 @@ trait AssertContentTrait {
       // DOM can load HTML soup. But, HTML soup can throw warnings, suppress
       // them.
       $html_dom = new \DOMDocument();
-      @$html_dom->loadHTML('<?xml encoding="UTF-8">' . $this->getRawContent());
+      @$html_dom->loadHTML('<?xml encoding="UTF-8">' . $this->getRawContent(), LIBXML_NOBLANKS);
       if ($html_dom) {
         // It's much easier to work with simplexml than DOM, luckily enough
         // we can just simply import our DOM tree.