There were two issues with the tests
1. Incorrect print formats causing incorrect output.
2. The RTC driver was not waiting for the shadow registers to be
updated after sleeping, their reset values to be read.
Depends on having:
1. An STM32 Nucleo with an STM32L412RB connected
2. A serial device connected to that board
3. A JLink connected to that board (no the onboard ST-Link!)
For now, there are some hardcoded paths, too.
