Make non-threaded VME interpreter work again

Make non-threaded VME interpreter work again

625bb0520708879ef5d281ab0c62fc7ad5415441 added a statement
to the QML_NEXT_INSTR macro without turning the macro
definition into a block. This caused statements like

if (foo)
    QML_NEXT_INSTR(bar);

to unexpectedly break from the switch (the second statement
in the QML_NEXT_INSTR expansion is "break").

Change-Id: I384280eaea1dd1f3b940be67d589f3a03d9e8685
Reviewed-by: Aaron Kennedy <aaron.kennedy@nokia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>