inconsistent module list when CLOSE loads itself indirectly. Refs: 143.
In a pathological case, the CLOSE section of a module may load
the module to be unloaded indirectly and thereby make the reference count > 0.
Such a module must not be unloaded but an error should be reported.
This situation is now checked after calling the terminator (CLOSE) of a module.
The resulting behavior is in line with the finalizer semantics and with the behavior
of a module terminator that generates a Trap:
the terminator of a module is called only once.

Signed-off-by: Josef Templ <josef.templ@gmail.com>