MC: Remove stream and output functions from MCObjectWriter. NFCI.

Part of PR37466.

Differential Revision: https://reviews.llvm.org/D47043

llvm-svn: 332864
diff --git a/llvm/lib/MC/WasmObjectWriter.cpp b/llvm/lib/MC/WasmObjectWriter.cpp
index f3ff3b9..a9ff7be 100644
--- a/llvm/lib/MC/WasmObjectWriter.cpp
+++ b/llvm/lib/MC/WasmObjectWriter.cpp
@@ -252,8 +252,7 @@
 public:
   WasmObjectWriter(std::unique_ptr<MCWasmObjectTargetWriter> MOTW,
                    raw_pwrite_stream &OS)
-      : MCObjectWriter(OS, /*IsLittleEndian=*/true), W(OS, support::little),
-        TargetObjectWriter(std::move(MOTW)) {}
+      : W(OS, support::little), TargetObjectWriter(std::move(MOTW)) {}
 
   ~WasmObjectWriter() override;