ext/*: Make X_from_obj(zend_object *obj) functions macros

[TimWolla]

With the introduction of the ZEND_CONTAINER_OF() macro we can now preserve whether or not the zend_object * is const when extracting the class-specific struct. This change will allow to use const zend_object * in more locations.

Changes performed with Coccinelle followed by some manual cleanup for comment and whitespace formatting:

@a@
attribute name zend_always_inline;
type T;
identifier obj;
identifier f;
typedef zend_object;
@@

 T* f(zend_object *obj) { return ZEND_CONTAINER_OF(obj, T, std); }
+ #define f(obj) ZEND_CONTAINER_OF(obj, T, std)

@@
identifier a.f;
@@

- f(...) { ... }

@b@
attribute name zend_always_inline;
type T;
identifier obj;
identifier f;
typedef zend_object;
@@

 T* f(zend_object *obj) { return ZEND_CONTAINER_OF(obj, T, zo); }
+ #define f(obj) ZEND_CONTAINER_OF(obj, T, zo)

@@
identifier b.f;
@@

- f(...) { ... }