[TLI][AArch64] Extend SLEEF vectorized functions mapping with VLA functions

This commit extends D134719 "[AArch64] Enable libm vectorized
functions via SLEEF" with the mappings for the scalable functions.

It also introduces all the necessary changes needed to support masked
interfaces.

Signed-off-by: Paul Osmialowski <pawel.osmialowski@arm.com>