Removing deprecated warning messages

Removed warning message related to use loadRelaxed() instead of .load() Files:

1. kdevplatform/language/backgroundparser/parsejob.cpp
2. kdevplatform/language/duchain/duchain.cpp
3. kdevplatform/language/duchain/duchainlock.cpp
4. kdevplatform/util/ksharedobject.h

Removed warning message related to use QElapsedTimer instead of QTimer. Files:

1. kdevplatform/tests/testfile.cpp
2. kdevplatform/shell/statusbar.h

Removed warning message related to use QSet (list.begin(), list.end()) instead of .toSet(). Files:

1. kdevplatform/language/codegen/documentchangeset.cpp