Kernel+SystemMonitor: Add fault counters

This patch adds three separate per-process fault counters:

- Inode faults

    An inode fault happens when we've memory-mapped a file from disk
    and we end up having to load 1 page (4KB) of the file into memory.

- Zero faults

    Memory returned by mmap() is lazily zeroed out. Every time we have
    to zero out 1 page, we count a zero fault.

- CoW faults

    VM objects can be shared by multiple mappings that make their own
    unique copy iff they want to modify it. The typical reason here is
    memory shared between a parent and child process.

Libraries/LibCore/CProcessStatisticsReader.h

@@ -24,6 +24,9 @@ struct CProcessStatistics {
     unsigned ticks;
     String priority;
     unsigned syscall_count;
+    unsigned inode_faults;
+    unsigned zero_faults;
+    unsigned cow_faults;
     int icon_id;
 
     // synthetic