Add [TypeChecking=Interface] to XSLTProcessor interface

LayoutTests/fast/xsl/xslt-processor-expected.txt

Index: LayoutTests/fast/xsl/xslt-processor-expected.txt
diff --git a/LayoutTests/fast/xsl/xslt-processor-expected.txt b/LayoutTests/fast/xsl/xslt-processor-expected.txt
index f9ddbeb8576ac3b56e14290544b07512ceb7f2fa..2eba7629c090273c14249c4b9b5cc4f3dbdda6bf 100644
--- a/LayoutTests/fast/xsl/xslt-processor-expected.txt
+++ b/LayoutTests/fast/xsl/xslt-processor-expected.txt
@@ -48,7 +48,7 @@ SOURCE XML: &lt;&lt;&lt;&amp;тест&amp;&gt;&gt;&gt;</pre>
 </body>
 </html>
 1.3 Import undefined stylesheet:
-****Failure**** (expected exception, instead got result: "undefined")
+Success
 1.4 Import undefined stylesheet:
 ****Failure**** (expected exception, instead got result: "undefined")
 1.5 Don't import stylesheet:
@@ -57,11 +57,11 @@ Success
 2.0 DOMDocumentFragment transformToFragment(in DOMNode source, in DOMDocument output):
 
 2.1 fragment with undefined source:
-****Failure**** (expected exception, instead got result: "null")
+Success
 2.2 fragment with undefined output document:
 Success
 2.3 use non-DOMDocument output parameter:
-****Failure**** (expected exception, instead got result: "null")
+Success
 2.4 transform to same fragment twice:
 Success
 2.5 transformed fragment containing only text:
@@ -72,7 +72,7 @@ Success
 3.0 DOMDocument transformToDocument(in DOMNode source):
 
 3.1 use non-DOMDocument output parameter:
-****Failure**** (expected exception, instead got result: "null")
+Success
 3.2 transform twice:
 Success