Adding RX backpressure test which replicates github issue 13

[pthedinger]

The current test results show that there are issues in more than just one configuration:

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TEST SUMMARY

lib_ethernet::basic_tests::test_rx_backpressure[mac=standard;arch=xs1;phy=mii;clk=25Mhz] FAIL lib_ethernet::basic_tests::test_rx_backpressure[mac=rt;arch=xs1;phy=mii;clk=25Mhz] FAIL lib_ethernet::basic_tests::test_rx_backpressure[mac=rt_hp;arch=xs1;phy=mii;clk=25Mhz] FAIL lib_ethernet::basic_tests::test_rx_backpressure[mac=standard;arch=xs2;phy=mii;clk=25Mhz] FAIL lib_ethernet::basic_tests::test_rx_backpressure[mac=rt;arch=xs2;phy=mii;clk=25Mhz] FAIL lib_ethernet::basic_tests::test_rx_backpressure[mac=rt_hp;arch=xs2;phy=mii;clk=25Mhz] FAIL lib_ethernet::basic_tests::test_rx_backpressure[mac=rt;arch=xs2;phy=rgmii;clk=25Mhz] PASS lib_ethernet::basic_tests::test_rx_backpressure[mac=rt_hp;arch=xs2;phy=rgmii;clk=25Mhz] PASS lib_ethernet::basic_tests::test_rx_backpressure[mac=rt;arch=xs2;phy=rgmii;clk=125Mhz] PASS lib_ethernet::basic_tests::test_rx_backpressure[mac=rt_hp;arch=xs2;phy=rgmii;clk=125Mhz] PASS

4/10 PASSED

[ahogen]

(just linking to the issue, for documentation's sake)

Related to issue #13

[larry-xmos]

Related to issue #13

@ahogen Thank you, the pull request title should have used '#13' that Github would automatically expand to a hyperlink

[larry-xmos]

All looks fine to me. It would be good to try AN00199 on the eXplorerKIT.