kselftest/arm64: Verify simultaneous SSVE and ZA context generation

Add a test that generates SSVE and ZA context in a single signal frame to
ensure that nothing is going wrong in that case for any reason.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230117-arm64-test-ssve-za-v1-2-203c00150154@kernel.org


Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>