With SAMD21 + CDC ACM the test reports
== printed in 2103454/2100000 µs ==
Which failed to match the requirement of <1.0015.
This commit relaxes the requirement to <1.002
The application is mainly to compile-test non-blocking UART
functionality, but some functional testing is also possible.
With non-blocking UART the total runtime of the program is 2100735 µs
on same54-xpro.
With blocking UART the total runtime is 2152407 µs.
