AK: Add Eternal<T> and use it in various places.

This is useful for static locals that never need to be destroyed:

Thing& Thing::the()
{
    static Eternal<Thing> the;
    return the;
}

The object will be allocated in data segment memory and will never have
its destructor invoked.

AK/kmalloc.h

@@ -8,6 +8,7 @@
 #define AK_MAKE_ETERNAL \
 public: \
     void* operator new(size_t size) { return kmalloc_eternal(size); } \
+    void* operator new(size_t, void* ptr) { return ptr; } \
 private:
 #else
 #define AK_MAKE_ETERNAL