Altered the comment to have fewer commitments in it.
Introduced a new type of location: SIMPLE-LOCATION.

It is a special case of LEXICAL-LOCATION.  A LEXICAL-LOCATION can be
changed into a SIMPLE-LOCATION if an analysis shows that it is only
used within a single function, so that no capture is possible.  A
location of this type can be allocated in a register or on the stack.
Creating a temporary creates a SIMPLE-LOCATION.
Introduced CAPTURED-LOCATION.