Wine would append a correctly aligned NUL Unicode character to
terminate the string but overflow the buffer by one byte for odd-sized
strings.
Windows instead overwrites the last two buffer bytes with a NUL Unicode
character which ends up being misaligned for odd-sized strings.
The clipboard data has a size field anyway so match the Windows
behavior.
Tweak the tests to show that SetClipboardData() can overwrite half of
the Unicode string's last character.