[llvm] [WebAssembly] Limit increase of Ctx.End (PR #76676)

[Derek Schuff via llvm-commits]

dschuff wrote:

This looks good to me in general.
I think I like the idea of using the unittest framework for testing parsing of possibly malformed binary files (as opposed to the alternative of checking in binary files somewhere like llvm/test/Object). @sbc100 does this seem reasonable to you?

https://github.com/llvm/llvm-project/pull/76676