[kernel] Fix frame allocation for multiple pages

There was an inverted boolean logic in determining how many consecutive
pages were available.

Also adding some memory debugging tools I added to track down the recent
memory bugs:

- A direct debugcon::write call, for logging to the debugcon without the
  possible page faults with the logger.
- A new vm_space::lock call, to make a page not fillable in memory
  debugging mode
- A mode in heap_allocator to always alloc new pages, and lock freed
  pages to cause page faults for use-after-free bugs.
- Logging in kobject on creation and deletion
- Page table cache structs are now page-sized for easy pointer math

src/kernel/objects/kobject.h

@@ -38,6 +38,8 @@ public:
         return static_cast<type>((koid >> koid_type_shift) & koid_type_mask);
     }
 
+    static const char * type_name(type t);
+
     /// Get this object's type
     inline type get_type() const { return m_type; }