[AArch64][SVE] NFC: tidy up isel lowering

Whilst adding legal types <-> register classes for Streaming SVE in
D118561 I noticed the hasSVE predication block set operation actions for
opcodes that may not be legal in Streaming SVE. Move these operations to
the later hasSVE block which has loops over the same types.

Reviewed By: sdesmalen

Differential Revision: https://reviews.llvm.org/D118560