The biggest change is the split from FunctionIndex to
DefinedFuncIndex to FuncIndex. Take better advantage of this by
converting several Vecs to PrimaryMaps.
Also, table_addr can now handle indices of the table index type,
so we don't need to explicitly uextend them anymore.
* Implement.
* Clean and doc
* Collect base addresses instead of leaking them
* Fix code for 1.25.
* Simplify $assert
* Use AbiParam::special.
* Use &mut self in base_addr
