Add qemu riscv64 testing support
## Issue description
CIP currently supports qemu riscv64 for CIP 5.10 and 6.1 kernels, but we only currently only build in our CI. We need to add testing support as well.
## Useful links
- CI pipelines are defined [here](https://gitlab.com/cip-project/cip-testing/linux-cip-pipelines)
- CI scripts, image and test templates are defined [here](https://gitlab.com/cip-project/cip-testing/linux-cip-ci)
## Acceptance criteria
- [ ] Add support for boot testing for qemu riscv, using isar-cip-core
(LTP and other test cases will be added by other issues)
issue