Simplify the prologue of emacs-module.c functions

Simplify the prologue of emacs-module.c functions

* emacs-module.c (MODULE_FUNCTION_BEGIN): New macro.
(module_make_global_ref)
(module_free_global_ref, module_make_function, module_funcall)
(module_intern, module_type_of, module_extract_integer)
(module_make_integer, module_extract_float, module_make_float)
(module_copy_string_contents, module_make_string)
(module_make_user_ptr, module_get_user_ptr, module_set_user_ptr)
(module_get_user_finalizer, module_set_user_finalizer)
(module_vec_set, module_vec_get, module_vec_size): Use new helper
macro MODULE_FUNCTION_BEGIN.