Add KeGetCurrentProcessorNumberEx to CQE-457 whitelist

Windows driver developers may call KeGetCurrentProcessorNumberEx in their driver.  This function optionally may initialize a provided structure, but this initialization always occurs.  The return value is the current processor being run on.  As such, this query incorrectly marks calls to KeGetCurrentProcessorNumberEx that initialize a structure that is later used as risky, even though in reality the initialization always succeeds.

See https://docs.microsoft.com/en-us/windows-hardware/drivers/ddi/ntddk/nf-ntddk-kegetcurrentprocessornumberex

cpp/ql/src/Security/CWE/CWE-457/InitializationFunctions.qll

@@ -353,7 +353,9 @@ class InitializationFunction extends Function {
           // Destination range is zeroed out on failure, assuming first two parameters are valid
           "memcpy_s",
           // This zeroes the memory unconditionally
-          "SeCreateAccessState"
+          "SeCreateAccessState",
+          // Argument initialization is optional, but always succeeds
+          "KeGetCurrentProcessorNumberEx"
         ]
     )
   }