[aarch64] Skip verify_sve_vector_length after native calls if SVE supports 128 bits VL only

The maximum SVE vector length "VLmax" is determined by the hardware: 16 <= VLmax <= 256.
The value of VL can be configured at runtime: 16 <= VL <= VLmax, where VL must be a multiple of 16.

Once we find CPU's VLMax is 16 bytes only, the verification "verify_sve_vector_length()" after native calls is not required - in other words, VL cannot be set to a value other than 16.