[wasm] Pass the context to ToJS.

[wasm] Pass the context to ToJS.

The original code assumed that the context that is needed in
wasm-compiler.cc in ToJS() can be acquired from the module_. However,
when ToJS() is used in the JSToWasm wrapper, module_ is not initialized.
With this CL the context is passed explicitly to ToJS().

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

[ahaas, 2016-08-22 07:35:21]

The CQ bit was checked by ahaas@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-08-22 07:35:25]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-08-22 07:58:15]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-08-22 07:58:16]

Dry run: This issue passed the CQ dry run.

[titzer, 2016-08-22 08:28:14]

https://codereview.chromium.org/2262103002/diff/1/src/compiler/wasm-compiler.cc
File src/compiler/wasm-compiler.cc (right):

https://codereview.chromium.org/2262103002/diff/1/src/compiler/wasm-compiler....
src/compiler/wasm-compiler.cc:2562: ToJS(retval, context,
Maybe this take a context_node, since we already have a context as an incoming
parameter.