Allow HPushArgument to handle more than one argument.

src/x64/lithium-x64.cc

Index: src/x64/lithium-x64.cc
diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index 4c1ae26d477fd6a3e9c0a1c8e9dca8ec9e6c7401..a3bd9f6b191dbd7b46da2062ccbec0e4f231f559 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -1023,9 +1023,13 @@ LInstruction* LChunkBuilder::DoApplyArguments(HApplyArguments* instr) {
 }
 
 
-LInstruction* LChunkBuilder::DoPushArgument(HPushArgument* instr) {
-  LOperand* argument = UseOrConstant(instr->argument());
-  return new(zone()) LPushArgument(argument);
+LInstruction* LChunkBuilder::DoPushArguments(HPushArguments* instr) {
+  int argc = instr->OperandCount();
+  for (int i = 0; i < argc; ++i) {
+    LOperand* argument = UseOrConstant(instr->argument(i));
+    AddInstruction(new(zone()) LPushArgument(argument), instr);
+  }
+  return NULL;
 }