[WebAssembly] Set LoadExt and TruncStore actions for SIMD types

Summary: Fixes part of the problem reported in bug 39275.

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits, alexcrichton

Differential Revision: https://reviews.llvm.org/D53542

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345230 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed