selftests/user_events: Test struct size match cases

The self tests for user_events currently does not ensure that the edge
case for struct types work properly with size differences.

Add cases for mis-matching struct names and sizes to ensure they work
properly.

Link: https://lkml.kernel.org/r/20230629235049.581-3-beaub@linux.microsoft.com



Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: linux-kselftest@vger.kernel.org
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>