Arrange that destructors of local C++ objects in the wrapper function
get run on SWIG_fail (which calls lua_error() which calls longjmp()).
We achieve this by putting almost everything in the function in its
own block, and end that right before lua_error() at which point those
destructors will get called.
The out typemap uses a function name which doesn't match the name of the
function we want it to apply to, so this testcase wasn't actually
triggering an exception so wasn't actually testing anything!
With that fixed, the testcase fails to compile for PHP due to use of
SWIG_exception_fail() (which not all target languages implement), and
with that fixed, the _runme.php needs a try ... catch adding to handle
the raised exception.