The Dart exception is converted to a string, stored in a trap which
is passed through wasm, then converted back to a Dart exception.
Module instantiation can also throw a trap, because it internally
invokes the initialization function, if the module defines one. So I'm
handling this too.
Also, update to the new version of the wasm C API, which replaces some
foo_t** with foo_vec_t*.
Bug: https://github.com/dart-lang/sdk/issues/37882
Change-Id: I1e6952a191134734a892c42b2fb8ba3506bb0844
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/169784
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Liam Appelbe <liama@google.com>