[PATCH] fix wide character literal use in some test cases

[Paolo Carlini]

Jan Beulich wrote:

>This abstracts the use of constants for calls to wmemset() in some of
>the test cases. On targets with 16-bit wide characters or with
>-fshort-wchar using 32-bit literals results in compiler warnings, respectively
>leading to failures of these tests.
>  
>
Humm, I have a feeling we can deal with this issue better, in particular
avoiding duplicating "C style" macros. Since there is nothing special
about 0xdeadbeef in such tests, what about just using 0xdead everywhere
and adding a one-line comment reminding the 16-bit wchar_t issue?

Paolo.