Simplify HInvokeStatic code generation.

HPushArgument is not needed for now (but might be when we start
optimizing). Also, calling convention for 64bits backend will
require to know more about the argument than the argument's
index. Therefore currently let HInvokeStatic setup the arguments,
which is possible because arguments of a calls are virtual registers
and not instructions.

Change-Id: I8753ed6083aa083c5180ab53b436dc8de4f1fe31
diff --git a/compiler/optimizing/builder.cc b/compiler/optimizing/builder.cc
index 637cf17..1efdd38 100644
--- a/compiler/optimizing/builder.cc
+++ b/compiler/optimizing/builder.cc
@@ -282,9 +282,7 @@
   size_t start_index = 0;
   if (is_instance_call) {
     HInstruction* arg = LoadLocal(is_range ? register_index : args[0], Primitive::kPrimNot);
-    HInstruction* push = new (arena_) HPushArgument(arg, 0);
-    current_block_->AddInstruction(push);
-    invoke->SetArgumentAt(0, push);
+    invoke->SetArgumentAt(0, arg);
     start_index = 1;
   }
 
@@ -305,9 +303,7 @@
           return false;
         }
         HInstruction* arg = LoadLocal(is_range ? register_index + i : args[i], type);
-        HInstruction* push = new (arena_) HPushArgument(arg, i);
-        current_block_->AddInstruction(push);
-        invoke->SetArgumentAt(argument_index, push);
+        invoke->SetArgumentAt(argument_index, arg);
         if (type == Primitive::kPrimLong) {
           i++;
         }