With the new wasm object types, the GetCompiledModule and GetWasmBytes
functions are not needed any more. The same functions are already
public on the wasm objects.
In order to use them properly, I changed a few more locations to make
use of the new types.

R=ahaas@chromium.org, titzer@chromium.org

Review-Url: https://codereview.chromium.org/2503403005
Cr-Commit-Position: refs/heads/master@{#41085}