LibJS: Remove unused header includes

Author: https://github.com/bgianfo
Commit: 53166c10ca
Pull-request: https://github.com/SerenityOS/serenity/pull/9120
Reviewed-by: https://github.com/AtkinsSJ ✅

Userland/Libraries/LibJS/Heap/BlockAllocator.cpp

@@ -6,10 +6,8 @@
 
 #include <AK/Platform.h>
 #include <AK/Vector.h>
-#include <LibJS/Forward.h>
 #include <LibJS/Heap/BlockAllocator.h>
 #include <LibJS/Heap/HeapBlock.h>
-#include <stdlib.h>
 #include <sys/mman.h>
 
 #ifdef HAS_ADDRESS_SANITIZER