Cleanup Whitespace in unittest/ directory

Cleanup unnecessary whitespace at the end of lines and end of files
in the unittest/ directory. Note that all code changes are
non-functional.

All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer Amazon Web
Services, Inc.

unittest/mysys/dynstring-t.c

@@ -71,4 +71,3 @@ int main(void)
 
   return exit_status();
 }
-