QTextStream autotest has outdated manipulators test case

In tests/auto/corelib/io/qtextstream/tst_qtextstream.cpp, the manipulators() test has commented-out test data relating to the way manipulators worked in Qt3. In Qt4 and Qt5, manipulators work very differently (see the "Related Non-Members" section of the QTextStream class documentation).

The manipulators() test function should be updated to test current set of QTextStream manipulators.