[WebAssembly] Parse llvm.ident into producers section

Summary:
Everything before the word "version" is the tool, and everything after
the word "version" is the version.

Reviewers: aheejin, dschuff

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

Differential Revision: https://reviews.llvm.org/D56742

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351399 91177308-0d34-0410-b5e6-96231b3b80d8
14 files changed