[WebAssembly] Add wasm support for llvm-readobj

Create a WasmDumper subclass of ObjDumper to support Webassembly binary
files.

Patch by Sam Clegg

Differential Revision: https://reviews.llvm.org/D27355

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293569 91177308-0d34-0410-b5e6-96231b3b80d8
10 files changed