[InterleaveAccess] Recognise Interleave loads through binary operations

[InterleaveAccess] Recognise Interleave loads through binary operations

Instcombine will currently sink identical shuffles though vector binary
operations. This is probably generally useful, but can break up the code
pattern we use to represent an interleaving load group. This patch
reverses that in the InterleaveAccessPass to re-recognise the pattern of
shuffles sunk past binary operations and folds them back if an
interleave group can be created.

Differential Revision: https://reviews.llvm.org/D89489