Start implementing realloc functions for Arena allocator

src/core/mem/arena/mem_arena.c

@@ -95,6 +95,14 @@ void *wapp_mem_arena_alloc_aligned(Arena *arena, u64 size, u64 alignment) {
   return (void *)output;
 }
 
+void *wapp_mem_arena_realloc(Arena *arena, void *ptr, u64 old_size, u64 new_size) {
+  return NULL;
+}
+
+void *wapp_mem_arena_realloc_aligned(Arena *arena, void *ptr, u64 old_size, u64 new_size, u64 alignment) {
+  return NULL;
+}
+
 void wapp_mem_arena_clear(Arena *arena) {
   if (!arena) {
     return;