Clang: Send the diagnostics delayed

Change-Id: I6065e51d38c262cf59d977c11c6453dec85a6dfe
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>

src/tools/clangbackend/ipcsource/clangipcserver.h

@@ -62,6 +62,7 @@ private:
     ProjectParts projects;
     UnsavedFiles unsavedFiles;
     TranslationUnits translationUnits;
+    QTimer sendDiagnosticsTimer;
 };
 
 } // namespace ClangBackEnd