http: fix stalled pipeline bug (v3.x backport)

[rvagg]

Backport of #3342 / ab03635, only including _http_outgoing.js changes as per @indutny's suggestion. cherry-pick wasn't clean so doing this as a new commit.

/R=@indutny

Original commit ab03635:

  This is a two-part fix:

  - Fix pending data notification in `OutgoingMessage` to notify server
    about flushed data too
  - Fix pause/resume behavior for the consumed socket. `resume` event is
    emitted on a next tick, and `socket._paused` can already be `true` at
    this time. Pause the socket again to avoid PAUSED error on parser.

  Fix: https://github.com/nodejs/node/issues/3332
  PR-URL: https://github.com/nodejs/node/pull/3342
  Reviewed-By: James M Snell <jasnell@gmail.com>
  Reviewed-By: Trevor Norris <trev.norris@gmail.com>

[indutny]

LGTM

[rvagg]

@indutny included test fails:

=== release test-http-pipeline-regr-3332 ===
Path: parallel/test-http-pipeline-regr-3332
assert.js:89
  throw new assert.AssertionError({
  ^
AssertionError: 32 == 10000
    at process.<anonymous> (/Users/rvagg/git/iojs/io.js/test/parallel/test-http-pipeline-regr-3332.js:40:10)
    at emitOne (events.js:82:20)
    at process.emit (events.js:169:7)
Command: out/Release/iojs /Users/rvagg/git/iojs/io.js/test/parallel/test-http-pipeline-regr-3332.js

is it expected that it would pass when included as is?

[indutny]

Checking

[indutny]

Wait, wut?! I didn't know that the parser consumption stuff was in v3... Sorry @rvagg, but the full patch should be ported then!

[rvagg]

closing, as per #3465 (comment)