- avoid relying on ASIO details in the main test (this is good anyway in
   terms of the original intent of asio link)
 - move internal-dependent tests to internal/tests with a workaround compiler
   flag

Also fixed a potentially common bug: use blocking recv() in recvUDP() with a fail safe timeout.  When compiled with clang++ this test sometimes failed due to the failure of recv(), and after looking at the code closely I found it possible to happen for other environments.


git-svn-id: svn://bind10.isc.org/svn/bind10/branches/trac448@4011 e5f2f494-b856-4b98-b285-d166d9295462