[tcp] tcpclient cannot connect to server on A101 and qemu

[qiaojingx]

Description

This is a regression issue. When running tcpclient on A101 and qemu, it can't connect to tcpserver at most of time.

Test Code

TCPClient6.js;
test-tcp6-client.js;

Steps to Reproduction

1. Build TCPClient6.js on A101 over BLE or Ethernet,
2. add router on Linux
3. patch tests/tools/tests-tcp6-server.py to use port 4242 which TCPClient6.js is expected
4. execute python tests/tools/tests-tcp6-server.py in 10s

Actual Result

Cannot connect to server at most of time.

Sometimes, test-tcp6-client.js can connect, but data transfer not work well.

Expected Result

Connection can be established. Data transfer works well

Test Builds

Branch	Commit Id	Target Device	Test Date	Result
master	fef1e19 - d04ae00	Arduino 101	Sep 4, 2017	Fail
master	fef1e19 - d04ae00	QEMU	Sep 4, 2017	Fail
master	8a3853f	Arduino 101	Sep 4, 2017	Pass
master	8a3853f	QEMU	Sep 4, 2017	Pass

Additional Information

[qiaojingx]

Verified with latest commit 087938a in master, TCPClient6 cannot connect to Server on Arduino101 over BLE.
It is able to connect on Arduino101 over Ethernet, but get cannot acquire send_buf error when send data.

[grgustaf]

Hmm, seems to work fine for me on A101 with Ethernet at least w/ latest. Possibly retry with PR #1522. I guess I'll try BLE also.

[grgustaf]

Shoot after I ran "make pristine" and rebuilt again, it no longer works. I do see the send_buf error.

[grgustaf]

Actually, that seems to be a fluke. Now it has worked several more times, including after another "make pristine".

[qiaojingx]

Verified with commit 0c0af9b in master. TCPClient6 on Arduino101 and 96b_carbon over BLE still cannot connect to TCPServer6.