Revert "EPROCESS: Fix is_valid check missing cast."

This reverts commit 60eda0a52b.

Turns out, this is pull request #110, only done worse.

volatility/framework/symbols/windows/extensions/__init__.py

@@ -696,7 +696,7 @@ class EPROCESS(generic.GenericIntelProcess, ExecutiveObject):
                 return False
 
             # check for all 0s besides the PCID entries
-            if self.Pcb.DirectoryTableBase.cast("unsigned long long") & ~0xfff == 0:
+            if self.Pcb.DirectoryTableBase & ~0xfff == 0:
                 return False
 
             ## TODO: we can also add the thread Flink and Blink tests if necessary