Kernel: Remove krealloc()

This was only used by a single class (AK::ByteBuffer) in the kernel
and not in an OOM-safe way.

Now that ByteBuffer no longer uses it, there's no need for the kernel
heap to burden itself with supporting this.

AK/kmalloc.h

@@ -17,7 +17,6 @@
 #    define kmalloc malloc
 #    define kmalloc_good_size malloc_good_size
 #    define kfree free
-#    define krealloc realloc
 
 inline void kfree_sized(void* ptr, size_t)
 {

Kernel/Heap/Heap.h

@@ -118,34 +118,6 @@ public:
         }
     }
 
-    template<typename MainHeap>
-    void* reallocate(void* ptr, size_t new_size, MainHeap& h)
-    {
-        if (!ptr)
-            return h.allocate(new_size);
-
-        auto* a = allocation_header(ptr);
-        VERIFY((u8*)a >= m_chunks && (u8*)ptr < m_chunks + m_total_chunks * CHUNK_SIZE);
-        VERIFY((u8*)a + a->allocation_size_in_chunks * CHUNK_SIZE <= m_chunks + m_total_chunks * CHUNK_SIZE);
-
-        size_t old_size = a->allocation_size_in_chunks * CHUNK_SIZE - sizeof(AllocationHeader);
-
-        if (old_size == new_size)
-            return ptr;
-
-        auto* new_ptr = h.allocate(new_size);
-        if (new_ptr) {
-            __builtin_memcpy(new_ptr, ptr, min(old_size, new_size));
-            deallocate(ptr);
-        }
-        return new_ptr;
-    }
-
-    void* reallocate(void* ptr, size_t new_size)
-    {
-        return reallocate(ptr, new_size, *this);
-    }
-
     bool contains(const void* ptr) const
     {
         const auto* a = allocation_header(ptr);
@@ -319,17 +291,6 @@ public:
         VERIFY_NOT_REACHED();
     }
 
-    void* reallocate(void* ptr, size_t new_size)
-    {
-        if (!ptr)
-            return allocate(new_size);
-        for (auto* subheap = &m_heaps; subheap; subheap = subheap->next) {
-            if (subheap->heap.contains(ptr))
-                return subheap->heap.reallocate(ptr, new_size, *this);
-        }
-        VERIFY_NOT_REACHED();
-    }
-
     HeapType& add_subheap(void* memory, size_t memory_size)
     {
         VERIFY(memory_size > sizeof(SubHeap));

Kernel/Heap/kmalloc.cpp

@@ -298,13 +298,6 @@ void kfree(void* ptr)
     --g_nested_kfree_calls;
 }
 
-void* krealloc(void* ptr, size_t new_size)
-{
-    kmalloc_verify_nospinlock_held();
-    ScopedSpinLock lock(s_lock);
-    return g_kmalloc_global->m_heap.reallocate(ptr, new_size);
-}
-
 size_t kmalloc_good_size(size_t size)
 {
     return size;

Kernel/Heap/kmalloc.h

@@ -40,7 +40,6 @@ void kmalloc_init();
 [[gnu::malloc, gnu::returns_nonnull, gnu::alloc_size(1)]] void* kmalloc_impl(size_t);
 [[gnu::malloc, gnu::returns_nonnull, gnu::alloc_size(1)]] void* kmalloc_eternal(size_t);
 
-void* krealloc(void*, size_t);
 void kfree(void*);
 void kfree_sized(void*, size_t);