Add a test for non-treelike behavior of stack (#961)

We've recently found a bug in a WebAssembly library we've been working
with where we're mapping WebAssembly to a tree-like IR internally. The
way we parse into this representation, however, has a bug when the
function isn't itself tree-like but rather exibits properties that
exploit a stack machine. For example this isn't so straightforward to
represent in a tree-like fashion:

    (import "" "a" (func $foo))
    (import "" "b" (func $foo (result i32)))
    (func (result i32)
      call $b
      call $b
      call $a
      i32.xor)

The extra `call $a` in the middle is valid `WebAssembly` but needs
special treatment when converting to a more tree-like IR format. I
figured it'd be good to ensure there's a spec test covering this case as
we currently pass the suite of spec tests but still contain this bug!

[interpreter] Don't suppress deprecation warnings

[interpreter] Make deprecation warning non-fatal

[interpreter] Unify assert_result* assertions (#1104)

[spec] Fix header level (#1047)

Add commands to generate Working Draft

* `make WD-tar`: Generate the Working Draft tar file to submit
* `make WD-echidna`: Publish the Working Draft via Echidna

Marking gh-pages used for fPWD

Fix a typo on landing page. (#692)

WebAssembly JS and Web integration spec in Bikeshed (#591)

* WebAssembly JS integraton spec in Bikeshed

Initial checkin, JS.bs is converted from JS.md with
updates to reference the current Wasm specification.

* Various cleanups/fixes:

- Ensure that not passing a maximum Memory size in the object will not
  create a maximum in Wasm.
- Clean up notes about object deduplication in instantiate.
- Refer to Promises guide everywhere.
- Remove duplicate buffer cloning.

* Improve threading

* Initial checkin of web interface

* Name WebAssembly CG as the editor (I'm not sure who should be editor)

* Fix formatting and queue instantiate(module) tasks appropriately

* Changes based on review from @domenic, @rossberg and @binji

* More changes from review by @domenic and @rossberg

* More changes from review

* Move

* More changes from review

- Formalize the process of getting a name for exported functions (including
  passing on the name of re-exported host functions)
- Link to ECMAScript bug for Memory detach behavior
- Some wording clarifications
- Extract out creation of a host function for clarity

* More precise wording for decoding success assertion

* Move specs to index.bs

* Respond to review feedback

* Respond to review from @annevk

* Respond to review from @lukewagner

[interpreter] Add missing dependency to install target (#588)