kselftest/arm64: Verify that we reject out of bounds VLs in sve-ptrace

We do not currently have a test that asserts that we reject attempts to set
a vector length smaller than SVE_VL_MIN or larger than SVE_VL_MAX, add one
since that is our current behaviour.

Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>