QmlCompiler: Wrap sequences with unknown elemnts in QVariantList

Otherwise we later try to perform value type lookups on them. That won't
work.

Task-number: QTBUG-110438
Change-Id: I1690a3375841ba5a1ff1a471a7f88bd2023ab4c4
Reviewed-by: Semih Yavuz <semih.yavuz@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
(cherry picked from commit c9b8b06117)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/qmlcompiler/qqmljstyperesolver.cpp

@@ -733,6 +733,7 @@ QQmlJSScope::ConstPtr QQmlJSTypeResolver::genericType(
                 break;
             }
         }
+        return m_variantListType;
     }
 
     return m_varType;

tests/auto/qml/qmlcppcodegen/data/badSequence.qml

@@ -3,4 +3,5 @@ import TestTypes
 Person {
     property Person other: Person { id: oo }
     barzles: oo.barzles
+    property int l: oo.barzles.length
 }

tests/auto/qml/qmlcppcodegen/tst_qmlcppcodegen.cpp

@@ -2473,6 +2473,7 @@ void tst_QmlCppCodegen::badSequence()
 
     other->setBarzles(barzles);
     QCOMPARE(self->barzles(), barzles);
+    QCOMPARE(self->property("l").toInt(), 2);
 }
 
 void tst_QmlCppCodegen::enumLookup()