QNetworkReplyHttpImpl: optimize QRingBuffer allocation

Use QSharedPointer<T>::create(), which co-locates the refcount with the payload
in a single memory allocation, instead of QSharedPointer<T>(new T), which causes
two allocations.

Change-Id: I280caf861b894f87996a9d3ae783943f55d54ff3
Reviewed-by: Peter Hartmann <phartmann@blackberry.com>
QNetworkReplyHttpImpl: optimize QAtomicInt allocation

Use QSharedPointer<T>::create(), which co-locates the refcount with the payload
in a single memory allocation, instead of QSharedPointer<T>(new T), which causes
two allocations.

Change-Id: I3f70d15a6d1bfaaa8b48a36ed3c877e817a5b701
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
tst_QSharedPointer: add more tests for forward-declared payloads

It is not sufficient that QSharedPointer<ForwardDeclared>'s default ctor
and dtor compile. Copy/move assignment/construction and swapping should work, too.

Arguably, there are more functions that should compile with just a forward-declared
payload, but this is a start.

Change-Id: I75470e3d4ba949c3e735c4078cbc123d53ec3007
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Do not assume that a class name is the first string in metaobject.

The patch removes unwritten requirements of having a class name as the
first string in qt_meta_stringdata_XXX::stringdata. It allows us to use
the name for suffix check in moc and potentially reduce the object size.

The patch actually fixes QMetaObject, so it properly interpret
classname field in qt_meta_data_XXX, which was previously ignored.

Change-Id: Id31aaf214b6d48c9dd1063ef9c00ec6b22738cbf
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>