<sigh> If only a test had been checked-in eight years ago ...

It looks like a number of things have to be changed in order to bring behavior back to what the docs promise.  Dict literals and dict comprehensions need to be fixed in both the compile.py and compile.c.  To avoid introducing a ROT_TWO, the store STORE_MAP and MAP_ADD opcodes need minor modifications (just switch the u and w variable assignments).