In order to have a wasm object (as JSObject), this adds a method to
instantiate the TestingModule. In order for this to work, the bytecode
and the function names of the TestingModule are stored for usage during
instantiation.

R=titzer@chromium.org

Review-Url: https://codereview.chromium.org/1916403002
Cr-Commit-Position: refs/heads/master@{#35906}