Static Thread methods and signal methods have been deprecated. Remove
all references in the main code, and most of the tests. Some tests of
the deprecated APIs themselves remain.
From lowercase to uppercase and drops 'test_'-prefix. Test case
descriptions do also match to TC names now.
Additionally all the TCs are not behing MBED_EXTENDED_TESTS
anymore.
Starts splitting Greentea test suites to TCP and UDP suites and adds
more test cases like
tcpsocket_echotest_burst
tcpsocket_echotest_burst_nonblock
tcpsocket_endpoint_close
tcpsocket_recv_100k
tcpsocket_recv_100k
tcpsocket_recv_timeout
tcpsocket_send_timeout
tcpsocket_thread_per_socket_safety
udpsocket_echotest_burst
udpsocket_echotest_burst_nonblock
udpsocket_recv_timeout
udpsocket_sendto_timeout