Removed WIN_HLP from mode flags passed to uifc.list() function:

This mode flag is only for use with ufic.showbuf(). Previously (before
revision 1.226 of uifc32.c), this would result in a NOOP, but when I
added "Cut" (to clipboard) support, I introduced WIN_CUT and used the
same bit value as WIN_HLP (since it wasn't used in uifc.list).

I noticed a new "Shift-DEL Cut" menu option appeared in SyncTERM (with
no corresponding way to paste) and this reuse of the WIN_HLP flag was the
reason why.