Update devrun to use latest node.js

[ochafik]

Updates:

• iojs was merged into node.js, v4 has good (enough) support for ES6 (note: can install with nvm: nvm install v4.0.0)
• flags needed update (+ bumped min version)
• globally-activated dartdevrun was failing to find its runtimeDir: fixed the corresponding logic.

[jmesserly]

does node 4 work with Karma now? I tried it last week, had to uninstall because of a socket.io bug:
socketio/socket.io#2213 (comment)
nodejs/node#2798

so upgrading node to 4 will break our browser tests :|

[ochafik]

Node4 still breaks karma, but when installing it with nvm in .travis.yml it doesn't seem to make it to the path so the tests still run fine.

(I've renamed NODE_BIN to NODE_4_BIN to make it clearer)

[jmesserly]

yeah, can see that it passes on Travis, just wondering what to do locally? if I were to install node 4 I won't be able to run our browser tests, but if I don't install it I won't be able to run dartdevrun.

Maybe we can wait a bit until the relevant fixes for nodejs/node#2798 land?

[ochafik]

Can wait or install both versions with nvm install v4.0.0; nvm install v0.12.7 and pass --v8-binary=$HOME/.nvm/versions/node/v4.0.0/bin/node (last one installed will be in path locally, can be switched with nvm use v0.12.7).

I've removed that part (will send as a separate PR on chromium reviews), kept the fixes for node 4 that I think should still go in :-)

[jmesserly]

Awesome! looks like everything merged now in upstream pkgs.