net: Conn.Close doesn't unblock Conn.Read on nacl

[bradfitz]

It appears that on nacl, a net.Conn.Close (on a "TCP" localhost conn) doesn't unblock a pending Conn.Read.

I thought we had a test for this and it worked, but I'm probably remembering a similar case instead.

Add a test & fix.

Failing higher-level test (skipped for now) is in net/http's TestServerSetKeepAlivesEnabledClosesConns.

Low priority (nacl).

[rsc]

Good for freeze I guess. That code should be going into syscall/net_nacl.go's netFile and then byteq.read and .close, and as far as I can tell, a close should be waking up a read.

[gopherbot]

CL https://golang.org/cl/33242 mentions this issue.