erlang_wasm 0.2.1

0.2.1

Changed

array.copy and array.fill do less work per element. Over ten thousand
elements, a copied element costs 7.0 reductions where it cost 19.9, and a
filled one 6.0 where it cost 7.8.

array.copy built three lists per copy and read the array's length from the
object table once per element, re-answering what the range check had already
answered. The loop lives in wasm_heap now, beside the accounting it has to go
through: it reads the source array's default once rather than per element, and
decides an overlapping copy by direction instead of taking a snapshot of the
source. A partial array.fill counts down rather than walking a list of the
indices it is about to use.

Behaviour does not change, including the rule that an overlapping array.copy
behaves as though an intermediate copy were taken.