Kernel: Rewrite x86_64 page tables to use HHDM instead of kmalloc

This allows page tables to not crash the kernel once kmalloc runs out of
its (limited) static memory.

kernel/arch/i686/PageTable.cpp

@@ -46,7 +46,7 @@ namespace Kernel
 		return result;
 	}
 
-	void PageTable::initialize()
+	void PageTable::initialize_pre_heap()
 	{
 		if (CPUID::has_nxe())
 			s_has_nxe = true;
@@ -65,6 +65,11 @@ namespace Kernel
 		s_kernel->initial_load();
 	}
 
+	void PageTable::initialize_post_heap()
+	{
+		// NOTE: this is no-op as our 32 bit target does not use hhdm
+	}
+
 	void PageTable::initial_load()
 	{
 		if (s_has_nxe)