CppEditor: Run test cases for virtual functions also with clangd

This uncovered some bugs, of which we fixed the ones that we could do
something about.

Change-Id: Id8494793bec4d25635bf920133d9f9331bd36228
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/cpptools/cppeditorwidgetinterface.h

@@ -31,7 +31,10 @@
 
 #include <QString>
 
-namespace TextEditor { class IAssistProvider; }
+namespace TextEditor {
+class IAssistProposal;
+class IAssistProvider;
+}
 
 namespace CppTools {
 
@@ -46,6 +49,11 @@ public:
 
     virtual void invokeTextEditorWidgetAssist(TextEditor::AssistKind assistKind,
                                               TextEditor::IAssistProvider *provider) = 0;
+
+    virtual void setProposals(const TextEditor::IAssistProposal *immediateProposal,
+                              const TextEditor::IAssistProposal *finalProposal) = 0;
+
+    bool inTestMode = false;
 };
 
 } // namespace CppTools

src/plugins/cpptools/cppvirtualfunctionassistprovider.cpp

@@ -113,7 +113,7 @@ public:
 
         auto *hintItem = new VirtualFunctionProposalItem(Utils::Link());
         hintItem->setText(QCoreApplication::translate("VirtualFunctionsAssistProcessor",
-                                                      "...searching overrides"));
+                                                      "collecting overrides ..."));
         hintItem->setOrder(-1000);
 
         QList<AssistProposalItemInterface *> items;