[WebAssembly] Read prefixed opcodes as ULEB128s

Summary: Depends on D54126.

Reviewers: aheejin, dschuff, aardappel

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

Differential Revision: https://reviews.llvm.org/D54138

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@346465 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed