AK: Remove bitrotted Traits::dump() mechanism

This was only used by HashTable::dump() which I used when doing the
first HashTable implementation. Removing this allows us to also remove
most includes of <AK/kstdio.h>.

Kernel/TestModule.cpp

@@ -25,7 +25,6 @@
  */
 
 #include <Kernel/Process.h>
-#include <LibBareMetal/Output/kstdio.h>
 
 extern "C" const char module_name[] = "TestModule";