AVX512 PacketMath add quarter type

Submitted by neu..@..eck.de

Assigned to Nobody

Link to original bugzilla bug (#1714)
Version: 3.4 (development)
Platform: x86 - AVX512

Description

AVX512 could define a quarter type since there are three usable types (ignoring suffixes):
__mm512
__mm256
__mm128

so dealing with a vector of ten double elements could be done by
one m512 and one m128 instruction/packet.

Depends on

#692