[LV] Don't have fold-tail under optsize invalidate interleave-groups when

[LV] Don't have fold-tail under optsize invalidate interleave-groups when
masked-interleaving is enabled

Enable interleave-groups under fold-tail scenario for Opt for size compilation;
D50480 added support for vectorizing loops of arbitrary trip-count without a
remiander, which in turn makes everything in the loop conditional, including
interleave-groups if any. It therefore invalidated all interleave-groups
because we didn't have support for vectorizing predicated interleaved-groups
at the time. In the meantime, D53011 introduced this support, so we don't
have to invalidate interleave-groups when masked-interleaved support is enabled.

Reviewers: Ayal, hsaito, dcaballe, fhahn

Reviewed By: hsaito

Differential Revision: https://reviews.llvm.org/D53559

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345115 91177308-0d34-0410-b5e6-96231b3b80d8