- Currently WebAssembly.Memory.grow() assumes that it always has an instance associated with it,
fix to grow and reflect new size when no instance is associated with memory object.
- Correctness fixes for the js api, throw range errors instead of generic errors
BUG=chromium:680938
R=bradnelson@chromium.org, titzer@chromium.org
Review-Url: https://codereview.chromium.org/2638243002
Cr-Commit-Position: refs/heads/master@{#42432}
