sim: Add some debug code to dump images

The code is commented out, but can easily be uncommented to allow the
various images to be dumped out for external analysis.
diff --git a/sim/src/main.rs b/sim/src/main.rs
index e33a39d..2c53d22 100644
--- a/sim/src/main.rs
+++ b/sim/src/main.rs
@@ -216,7 +216,9 @@
     let mut fl = flash.clone();
     c::set_flash_counter(0);
 
-    for _ in 0 .. count {
+    // fl.write_file("image0.bin").unwrap();
+    for i in 0 .. count {
+        info!("Running boot pass {}", i + 1);
         assert_eq!(c::boot_go(&mut fl, &areadesc), 0);
     }
     fl