Kernel: Remove spurious ProcessInspectionHandle

The class was removed in 538b985487fd958a7e8663a32867ac39d6643d04.

Kernel/Forward.h

@@ -51,7 +51,6 @@ class PerformanceEventBuffer;
 class PhysicalPage;
 class PhysicalRegion;
 class Process;
-class ProcessInspectionHandle;
 class ThreadTracer;
 class Range;
 class RangeAllocator;