Fix failing tst_qqmlecmascript::deleteRootObjectDuringCreation unit test

Respect the rootObjectInCreation flag in QQmlData. Centralize the checking code
for that through the places in the engine where it is checked, along with the
indestructible flag.

Change-Id: Ie977b34ac8d070f6dcd7bab11a95dd27ca25145e
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Cleanup: Remove dead code in QObject ownership handling

The ownership management of QObject JS wrappers is implemented in the engine
now and doesn't require external GC callbacks anymore or extra book keeping
data structures.

Change-Id: If04a09deec6c0342274daa4ed82a34d3503e32e9
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Fix tst_qqmlecmascript::switchStatement()

Adjust the expected error message output to include the column number
instead of just the line number.

Change-Id: Ie8064d6a26f875d8da5b0d68c503d632b6afc69e
Reviewed-by: Lars Knoll <lars.knoll@digia.com>