[reference-types] Support passive elem segments (#3572)

Passive element segments do not belong to any table, so the link between
Table and elem needs to be weaker; i.e. an elem may have a table in case
of active segments, or simply be a collection of function references in
case of passive/declarative segments.

This PR takes Table::Segment out and turns it into a first class module
element just like tables and functions. It also implements early support
for parsing, printing, encoding and decoding passive/declarative elem
segments.

0 files changed, 0 insertions, 0 deletions