Merge #11363: net: Split socket create/connect

Merge #11363: net: Split socket create/connect

3830b6e net: use CreateSocket for binds (Cory Fields)
df3bcf8 net: pass socket closing responsibility up to caller for outgoing connections (Cory Fields)
9e3b2f5 net: Move IsSelectableSocket check into socket creation (Cory Fields)
1729c29 net: split socket creation out of connection (Cory Fields)

Pull request description:

  Requirement for #11227.

  We'll need to create sockets and perform the actual connect in separate steps, so break them up.

  #11227 adds an RAII wrapper around connection attempts, as a belt-and-suspenders in case a CloseSocket is missed.

Tree-SHA512: de675bb718cc56d68893c303b8057ca062c7431eaa17ae7c4829caed119fa3f15b404d8f52aca22a6bca6e73a26fb79e898b335d090ab015bf6456cf417fc694