[WebAssembly] Store section alignment as a power of 2

This change bumps for version number of the wasm object file
metadata.

See https://github.com/WebAssembly/tool-conventions/pull/92

Differential Revision: https://reviews.llvm.org/D56758

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351285 91177308-0d34-0410-b5e6-96231b3b80d8
26 files changed