Fix tst_qqmldebugjs and tst_qquickfolderlistmodel build for WinCE.

Fix tst_qqmldebugjs and tst_qquickfolderlistmodel build for WinCE.

tst_qqmldebugjs:
    Some WINCE header files define IN and OUT macros, and those make
    the following assignments in tst_qqmldebugjs.cpp to fail later on:
        const char *IN = "in"
        const char *OUT = "out"
    Since platform macros are not needed in the context of this file,
    undef them to make build pass for WinCE.

tst_qquickfolderlistmodel:
    WinCE does nothave drive letter concept, so lets execute the
    changeDrive test only on desktop Windows.

Change-Id: I5c159e3b3ee82e888aeac1da559fd63a875d089e
Reviewed-by: Björn Breitmeyer <bjoern.breitmeyer@kdab.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Andreas Holzammer <andreas.holzammer@kdab.com>