Extends migration tests for flm and flt services

qt6-after/qt6-migrated-legatus/tests/test_qt6_api_migrations.cpp

@@ -50,8 +50,11 @@ TEST(Qt6ApiMigrations, QStringViewBasic)
     QStringView subView = view.mid(6, 4); // "Qt6 "
     EXPECT_EQ(subView.toString(), QStringLiteral("Qt6 "));
 
-    // Test that view doesn't allocate memory
-    EXPECT_EQ(view.data(), original.data());
+    // Test that view doesn't allocate memory: QStringView is a non-owning
+    // view onto the original's buffer. Note: the non-const QString::data()
+    // detaches the shared QString (copy-on-write) and would move the buffer,
+    // so the comparison has to use the const overload (constData()).
+    EXPECT_EQ(view.data(), original.constData());
 }
 
 // Test 2: QStringView with function parameters