Contribution description

When building tests/conn_can for native, it would fail because of unsatisfied feature requirements:

There are unsatisfied feature requirements: periph_can periph_gpio_irq

Adding an extra check for BOARD=native solves this problem.
Remove these feature requirements all together, since they are not needed here (see conversation below).
update 7/02:

• CI brought some ancient mistakes to our attention. Fixed these also up in a seperate commit.
• Removing "FEATURES_REQUIRED" loosened the restriction on boards that should support this test. However, not all boards have sufficient memory --> updated the BOARDS_INSUFFICIENT_MEMORY list.
• add arch_msp430 to FEATURES_BLACKLIST

Testing procedure

• Build on native before patch --> fail
• Build on native after patch --> success