tests: kernel.common.stack_sentinel: re-enable some platforms

This commit re-enables the following platforms for the
`kernel.common.stack_sentinel` test:
* `hifive1`
* `m2gl025_miv`

These platforms working correctly after Renode was upgraded to 1.15.2 in
the CI.

Signed-off-by: Filip Kokosinski <fkokosinski@antmicro.com>