xsim tx tests

[TDW89]

initial tx test runs builds and runs a .xe at sample rates [44100, 48000, 88200, 96000, 176400, 192000] looking for a ramp

• [x] manual test of jenkins file

TODO

• [x] documentation
• [x] make test aware of expected no of samples
• [x] improve detail on failure
• [x] rx tests
• [x] test with busy threads
• [ ] test rx with input jitter

[danielpieczko]

I've pushed my changes onto this pull request:

• support lists of stream data to transmit and check in Spdif_tx and Port_monitor
• add new testcases that run a pair of streams with a short gap between, checking that a block of subframes is seen on both
• removed dummy thread parameters in Python test code and run the receiver app at 300 MHz
• added recorded streams with and without jitter
• cleanup of capture.py and readback.py, removing hard-coded filenames
• run linter and formatter on Python files

[xross]

@TDW89 you can't be added as a reviewers as its your PR, please take a look.