stdio: Fix issue #3584. Use synch write in pipe

[HenryRawas]

When pipe used for stdout or stderr on Windows,
pipe does not allow IOCP. In this case do write
on calling thread.
Added test test-child-process-stdout-flush-exit

[trevnorris]

@HenryRawas in the future if there's anything you need to correct in the PR, go ahead and make the change then use git commit --amend then git push -f origin issue3584. GitHub will automatically pick up the change and they'll show up here.

[bnoordhuis]

Use two space indent. Changes to libuv should be submitted as a separate pull request to https://github.com/joyent/libuv (and preferably come with a test, though that may be somewhat difficult here.)

[piscisaureus]

Agree on that this needs to be fixed in node, but very much disagree with the implementation. This makes all pipe writes synchronous, not just the ones that we use for stdio.

[piscisaureus]

BTW hello @HenryRawas what have you been up to? :)

[HenryRawas]

I don't agree that all pipe writes are synchronous - only ones with mode FILE_SYNCHRONOUS_IO. I think pipes opened by libuv will not have this set.

Hello Bert. I have done work on Redis and some other stuff for MsOpenTech.

[HenryRawas]

After discussing with Bert I updated the pull request so that the pipe uses blocking writes only if the caller asks for it.
The fix is now split into 2. There is a libuv PR to change the pipe code, and a node PR to set the blocking flag for the pipe on stdout.

[tjfontaine]

fixed in a different way on master