fix #H1419 - missing object sanity checks for nested containers (trunk only)

fix #H1419 - missing object sanity checks for nested containers (trunk only)

     From a bug report, wizard mode's sanity_check
option has a check for container contents but wasn't using it recursively
for nested containers, so the contents of the latter weren't checked.
This fixes that, and also adds a check for objects carried by migrating
monsters.  And it now formats objects and monsters fully even if the hero
happens to be blind or hallucinating at the time.

     Tested by using a debugger to poke in various bits of invalid data.