If we are passed SHGFI_PIDL, szFullPath is not initialized. If we're passed
the flags PIDL, USEFILEATTRIBUTES, and an icon flag, we will try to use the
uninitialized filename to get the icon. Since the test claims that the
function should return an icon in this case, and we cannot always convert
a pidl to a path, we should just use the pidl.

Opening a storage when it has already been opened now fails with
STG_E_ACCESSDENIED. If we attempt to copy a storage to its own child, this
will happen during the copy.

Spotted by valgrind.

+/- aren't affected by customdraw settings, only per control
set colors used.

After query current tracking state passed parameters could be overwritten,
similar fix for Listview was recently committed.

Found by Valgrind.

Found by Valgrind.

Found by Valgrind.

Found by Valgrind.

Found by Valgrind.