Kernel: Invalidate file-backed VMO's when inodes are written.

The current strategy is simply to nuke all physical pages and force
reload them from disk. This is obviously not optimal and should eventually
be optimized. It should be fairly straightforward.

Kernel/Process.cpp

@@ -945,6 +945,7 @@ void Process::push_value_on_stack(dword value)
 void Process::crash()
 {
     ASSERT_INTERRUPTS_DISABLED();
+    ASSERT(is_ring3());
     ASSERT(state() != Dead);
     m_termination_signal = SIGSEGV;
     dump_regions();