Fix trapping and dangling insts in memory packing (#2540)

This does two things:
- Restore `visitDataDrop` handler deleted in #2529, but now we convert
  invalid `data.drop`s to not `unreachable` but `nop`. This conforms to
  the revised spec that `data.drop` on the active segment can be treated
  as a nop.
- Make `visitMemoryInit` trap if offset or size are not equal to 0 or if
  the dest address is out of bounds. Otherwise drop all its argument.

Fixes #2535.

0 files changed, 0 insertions, 0 deletions