"Implement" the HandlerData Win64 EH method in the base MCStreamer.

There's really nothing to implement. All this really does is swap to a
pseudo-section that later gets written to the unwind info struct. That
needs to be implemented in the object streamers.

llvm-svn: 131734

llvm/lib/MC/MCStreamer.cpp

@@ -369,8 +369,7 @@ void MCStreamer::EmitWin64EHHandler(const MCSymbol *Sym, bool Unwind,
 }
 
 void MCStreamer::EmitWin64EHHandlerData() {
-  errs() << "Not implemented yet\n";
-  abort();
+  EnsureValidW64UnwindInfo();
 }
 
 void MCStreamer::EmitWin64EHPushReg(unsigned Register) {