Remove growing_arena and use base_arena

src/mem/arena/mem_arena.h

@@ -8,7 +8,7 @@
 extern "C" {
 #endif // __cplusplus
 
-typedef struct growing_arena Arena;
+typedef struct arena Arena;
 
 bool wapp_mem_arena_init(Arena **arena, u64 base_capacity);
 void *wapp_mem_arena_alloc(Arena *arena, u64 size);