Even more workaround for clang warnings about typeid() side effects.

Even after 5aae7c7387 and
d2c1fce24e clang would still emit the
warning in code using templates via
WX_DECLARE_ANY_VALUE_TYPE(wxAnyValueTypeImpl<T>).

Silence the warning by putting the typeid() expressions into a trivial
helper function with two wxAnyValueType reference arguments, so the
class the macro is used in doesn't come into play (it shouldn't in the
previous version of the code either, but clang apparently thought it
did).

Hopefully really closes #16968.

include/wx/any.h

@@ -159,15 +159,17 @@ private:
 public: \
     static bool IsSameClass(const wxAnyValueType* otherType) \
     { \
-        const wxAnyValueType& inst = *sm_instance.get(); \
-        const wxAnyValueType& otherRef = *otherType; \
-        return wxTypeId(inst) == wxTypeId(otherRef); \
+        return AreSameClasses(*sm_instance.get(), *otherType); \
     } \
     virtual bool IsSameType(const wxAnyValueType* otherType) const wxOVERRIDE \
     { \
         return IsSameClass(otherType); \
     } \
 private: \
+    static bool AreSameClasses(const wxAnyValueType& a, const wxAnyValueType& b) \
+    { \
+        return wxTypeId(a) == wxTypeId(b); \
+    } \
     static wxAnyValueTypeScopedPtr sm_instance; \
 public: \
     static wxAnyValueType* GetInstance() \