Fix InstructionSelector to handle calls with no (used) output values.

src/compiler/x64/instruction-selector-x64.cc

Index: src/compiler/x64/instruction-selector-x64.cc
diff --git a/src/compiler/x64/instruction-selector-x64.cc b/src/compiler/x64/instruction-selector-x64.cc
index c84edfe839005d671e5f88700ed74de20f1d75a4..a25eaefd629aee38ef0b6b2c3326897258b70d93 100644
--- a/src/compiler/x64/instruction-selector-x64.cc
+++ b/src/compiler/x64/instruction-selector-x64.cc
@@ -764,8 +764,10 @@ void InstructionSelector::VisitCall(Node* node) {
   opcode |= MiscField::encode(descriptor->flags());
 
   // Emit the call instruction.
+  InstructionOperand** first_output =
+      buffer.outputs.size() > 0 ? &buffer.outputs.front() : NULL;
   Instruction* call_instr =
-      Emit(opcode, buffer.outputs.size(), &buffer.outputs.front(),
+      Emit(opcode, buffer.outputs.size(), first_output,
            buffer.instruction_args.size(), &buffer.instruction_args.front());
   call_instr->MarkAsCall();
 }