With this CL we use isolate->native_context() to provide a context for
the CEntryStub of the runtime call. The native_context() is sufficient
here because Runtime::kWasmThrowTypeError does not use the context.

R=titzer@chromium.org
TEST=mjsunit/wasm/ffi-error.js
BUG=chromium:639492

Review-Url: https://codereview.chromium.org/2291043002
Cr-Commit-Position: refs/heads/master@{#39014}