Inital rp23 ci tests

Some tests need more work.
* The adc test builds, but isn't set up correctly for the 2350 hardware
  yet.
* The multicore and gpio_multicore tests only work from flash,
  seems to be a probe-rs issue.
* The i2c and flash tests also only works from flash, these are probably
  bugs but I don't have time to run them down now.
* The 2350 gpio test skips anything with pull downs. I think these fail
  because of E9.

The float, bootsel, cyw43, and ethernet tests don't have 2350 equivalents.
There's no reason to use the float romfuncs, use the FPU.
Bootsel as a button isn't supported on the 2350 yet.
The wifi and eth tests don't have appropriate hardware.

The i2c test has also been tweaked to run on one core.

this removed the RelocatedProgram construction step from pio uses.
there's not all that much to be said for the extra step because the
origin can be set on the input program itself, and the remaining
information exposed by RelocatedProgram can be exposed from
LoadedProgram instead (even though it's already available on the pio_asm
programs, albeit perhaps less convenient). we do lose access to the
relocated instruction iterator, but we also cannot think of anything
this iterator would actually be useful for outside of program loading.