Update Greentea netsocket and wifi tests

[juhaylinen]

Description

Increase timeout for netsocket TCP and UDP tests. Old timeout
(240 seconds) was not enough for slower devices to complete the
tests.
Accept error codes NSAPI_ERROR_CONNECTION_TIMEOUT and
NSAPI_ERROR_NO_CONNECTION when running test wifi_connect_secure_fail

Pull request type

[x] Fix
[ ] Refactor
[ ] New target
[ ] Feature
[ ] Breaking change

[juhaylinen]

@SeppoTakalo please review

[0xc0170]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 2413
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/7283/

Triggering tests

/morph test
/morph uvisor-test
/morph export-build
/morph mbed2-build

[mbed-ci]

Exporter Build : SUCCESS

Build number : 2045
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/7283/

[mbed-ci]

Test : SUCCESS

Build number : 2196
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/7283/2196