[WebAssembly] Add llvm-objdump support for wasm file format

This is the first part of an effort to add wasm binary
support across all llvm tools.

Patch by Sam Clegg

Differential Revision: https://reviews.llvm.org/D26172

llvm-svn: 288251
diff --git a/llvm/lib/Object/Binary.cpp b/llvm/lib/Object/Binary.cpp
index 2d2192d..8467d34 100644
--- a/llvm/lib/Object/Binary.cpp
+++ b/llvm/lib/Object/Binary.cpp
@@ -63,6 +63,7 @@
     case sys::fs::file_magic::coff_import_library:
     case sys::fs::file_magic::pecoff_executable:
     case sys::fs::file_magic::bitcode:
+    case sys::fs::file_magic::wasm_object:
       return ObjectFile::createSymbolicFile(Buffer, Type, Context);
     case sys::fs::file_magic::macho_universal_binary:
       return MachOUniversalBinary::create(Buffer);