(Found by PreFast.)

The comparison should be (D3D_OK == hr && myDevice), not (D3D_OK == (hr && myDevice)).
(Found with PreFast.)

Therefore fix the code to handle SetPropW failing with this in mind.
(Found by PreFast.)

Some versions of ole32 don't test that the lindex field of the
FORMATETC structure passed into functions is valid.

As a window being registered for drag and drop is a system-global
property, the tests could be affected by other processes in the
system.

This fixes a hang (and sometimes a system hang) on MacOSX when running
the inetmib1 tests.  Spotted by Owen Rudge.