ALways ON : sql server 2012 SP2 stand alone servers quorum config scenario?

--ALways ON : sql server 2012 SP2  stand alone servers on win 2012 servers.

Version: SQL Server 2012 SP2 on windows 2012

Test Scenario:
Node1:
  TestDB
Node2:
TestDB
NOde3:
Other databases
Notes:
Always on configured from Node1 to Node3 on TestDB database.
NOde1,NOde2 and Node3 are standalone servers, not shared storage.

**Question:**
For autmoatic fail over purpose,can we use Node3 as Node majarity in Cluster Quorum configuration for configuring the always ON NOde1 to NOde2?
(We tried using Fileshare and working fine,but want to use 3rd server(node3--sql server intalled) as NOde majority)
i.e, NOde3 does it requred TestDB database or not not ?

thanks