LibJS: Don't generate unused HeapBlock names on non-SerenityOS systems

These are just ignored by the BlockAllocator anyway.

Userland/Libraries/LibJS/Heap/HeapBlock.cpp

@@ -20,8 +20,12 @@ namespace JS {
 
 NonnullOwnPtr<HeapBlock> HeapBlock::create_with_cell_size(Heap& heap, size_t cell_size)
 {
+#ifdef __serenity__
     char name[64];
     snprintf(name, sizeof(name), "LibJS: HeapBlock(%zu)", cell_size);
+#else
+    char const* name = nullptr;
+#endif
     auto* block = static_cast<HeapBlock*>(heap.block_allocator().allocate_block(name));
     new (block) HeapBlock(heap, cell_size);
     return NonnullOwnPtr<HeapBlock>(NonnullOwnPtr<HeapBlock>::Adopt, *block);