loplugin: use TypeCheck instead of getQualifiedNameAsString

since the latter is rather slow

Change-Id: Ib73cdb923585580777c2265b561c1808e93b2baa
Reviewed-on: https://gerrit.libreoffice.org/33585
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

compilerplugins/clang/cppunitassertequals.cxx

@@ -13,6 +13,7 @@
 #include <fstream>
 #include <set>
 #include "plugin.hxx"
+#include "check.hxx"
 
 /**
   Check for calls to CPPUNIT_ASSERT when it should be using CPPUNIT_ASSERT_EQUALS
@@ -87,7 +88,9 @@ void CppunitAssertEquals::checkExpr(const Stmt* stmt)
         return;
     }
     const FunctionDecl* functionDecl = callExpr->getDirectCallee()->getCanonicalDecl();
-    if (!functionDecl || functionDecl->getQualifiedNameAsString().find("Asserter::failIf") == std::string::npos) {
+    if (!functionDecl ||
+        !loplugin::DeclCheck(functionDecl).Function("failIf").Namespace("Asserter").Namespace("CppUnit").GlobalNamespace())
+    {
         return;
     }
     report(