Core: Fixed problem with ParseXML hanging on single endtag

autotest/ParseXMLErrors/Etalon.log

@@ -0,0 +1,5 @@
+* C:\upp\out\autotest\CLANGx64.Debug.Debug_Full\ParseXMLErrors.exe 03.10.2023 00:45:27, user: cxl
+
+xml =  <b> </b> 
+xml = </b>
+e = Unexpected text

autotest/ParseXMLErrors/ParseXMLErrors.cpp

@@ -0,0 +1,20 @@
+#include <Core/Core.h>
+
+using namespace Upp;
+
+CONSOLE_APP_MAIN
+{
+	StdLogSetup(LOG_FILE | LOG_COUT);
+
+	for(const char *xml : { " <b> </b> ", "</b>"  })
+		try {
+			DDUMP(xml);
+			ParseXML(xml);
+		}
+		catch(XmlError e)
+		{
+			DDUMP(e);
+		}
+	
+	CheckLogEtalon();
+}

autotest/ParseXMLErrors/ParseXMLErrors.upp

@@ -0,0 +1,10 @@
+uses
+	Core;
+
+file
+	Etalon.log,
+	ParseXMLErrors.cpp;
+
+mainconfig
+	"" = "";
+

uppsrc/Core/XML.cpp

@@ -1012,7 +1012,8 @@ static XmlNode sReadXmlNode(XmlParser& p, ParseXmlFilter *filter, dword style)
 		m.Shrink();
 		return m;
 	}
-	p.ReadText(); // skip empty text
+	if(p.ReadText().GetCount() == 0) // skip empty text
+		throw XmlError("Unexpected text");
 	return m;
 }