[proxy] fixing harmony/proxy.js tests and improving error messages + some drive-by fixes

src/full-codegen/ia32/full-codegen-ia32.cc

Index: src/full-codegen/ia32/full-codegen-ia32.cc
diff --git a/src/full-codegen/ia32/full-codegen-ia32.cc b/src/full-codegen/ia32/full-codegen-ia32.cc
index 28fbe85bbe6d53b6e7b79380bbf9139b3d2aca2f..7943f0b2e173c73118520a33e2fa9f5e23b98a7b 100644
--- a/src/full-codegen/ia32/full-codegen-ia32.cc
+++ b/src/full-codegen/ia32/full-codegen-ia32.cc
@@ -1026,7 +1026,6 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ jmp(&exit);
 
   // We got a fixed array in register eax. Iterate through that.
-  Label non_proxy;
   __ bind(&fixed_array);
 
   // No need for a write barrier, we are storing a Smi in the feedback vector.
@@ -1034,15 +1033,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   int vector_index = SmiFromSlot(slot)->value();
   __ mov(FieldOperand(ebx, FixedArray::OffsetOfElementAt(vector_index)),
          Immediate(TypeFeedbackVector::MegamorphicSentinel(isolate())));
-
-  __ mov(ebx, Immediate(Smi::FromInt(1)));  // Smi indicates slow check
-  __ mov(ecx, Operand(esp, 0 * kPointerSize));  // Get enumerated object
-  STATIC_ASSERT(JS_PROXY_TYPE == FIRST_JS_RECEIVER_TYPE);
-  __ CmpObjectType(ecx, JS_PROXY_TYPE, ecx);
-  __ j(above, &non_proxy);
-  __ Move(ebx, Immediate(Smi::FromInt(0)));  // Zero indicates proxy
-  __ bind(&non_proxy);
-  __ push(ebx);  // Smi
+  __ push(Immediate(Smi::FromInt(1)));  // Smi(1) indicates slow check
   __ push(eax);  // Array
   __ mov(eax, FieldOperand(eax, FixedArray::kLengthOffset));
   __ push(eax);  // Fixed array length (as smi).
@@ -1071,12 +1062,6 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ cmp(edx, FieldOperand(ecx, HeapObject::kMapOffset));
   __ j(equal, &update_each, Label::kNear);
 
-  // For proxies, no filtering is done.
-  // TODO(rossberg): What if only a prototype is a proxy? Not specified yet.
-  DCHECK(Smi::FromInt(0) == 0);
-  __ test(edx, edx);
-  __ j(zero, &update_each);
-
   // Convert the entry to a string or null if it isn't a property
   // anymore. If the property has been removed while iterating, we
   // just skip it.