tests: add zephyr uart driver api test case

This commit verifies the following uart driver apis:
	uart_irq_callback_set()
	uart_irq_rx_enable()
	uart_irq_rx_disable()
	uart_irq_rx_ready()
	uart_irq_tx_enable()
	uart_irq_tx_disable()
	uart_irq_tx_ready()
	uart_fifo_fill()
	uart_fifo_read()
	uart_irq_update()
	uart_poll_in()
	uart_poll_out()

Change-Id: I9be9341aee4357f86a2bc49f19733fb84273e89c
Signed-off-by: Qiu Peiyang <peiyangx.qiu@intel.com>