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

src/full-codegen/arm/full-codegen-arm.cc

Index: src/full-codegen/arm/full-codegen-arm.cc
diff --git a/src/full-codegen/arm/full-codegen-arm.cc b/src/full-codegen/arm/full-codegen-arm.cc
index acd877f62b3e79a30775456ab940d385ca94509a..7ab7fc65ab71b1fc3b07096ea98929c8665e9b59 100644
--- a/src/full-codegen/arm/full-codegen-arm.cc
+++ b/src/full-codegen/arm/full-codegen-arm.cc
@@ -1100,21 +1100,13 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ jmp(&exit);
 
   // We got a fixed array in register r0. Iterate through that.
-  Label non_proxy;
   __ bind(&fixed_array);
 
   __ EmitLoadTypeFeedbackVector(r1);
   __ mov(r2, Operand(TypeFeedbackVector::MegamorphicSentinel(isolate())));
   int vector_index = SmiFromSlot(slot)->value();
   __ str(r2, FieldMemOperand(r1, FixedArray::OffsetOfElementAt(vector_index)));
-
-  __ mov(r1, Operand(Smi::FromInt(1)));  // Smi indicates slow check
-  __ ldr(r2, MemOperand(sp, 0 * kPointerSize));  // Get enumerated object
-  STATIC_ASSERT(JS_PROXY_TYPE == FIRST_JS_RECEIVER_TYPE);
-  __ CompareObjectType(r2, r3, r3, JS_PROXY_TYPE);
-  __ b(gt, &non_proxy);
-  __ mov(r1, Operand(Smi::FromInt(0)));  // Zero indicates proxy
-  __ bind(&non_proxy);
+  __ mov(r1, Operand(Smi::FromInt(1)));  // Smi(1) indicates slow check
   __ Push(r1, r0);  // Smi and array
   __ ldr(r1, FieldMemOperand(r0, FixedArray::kLengthOffset));
   __ mov(r0, Operand(Smi::FromInt(0)));
@@ -1146,11 +1138,6 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ cmp(r4, Operand(r2));
   __ b(eq, &update_each);
 
-  // For proxies, no filtering is done.
-  // TODO(rossberg): What if only a prototype is a proxy? Not specified yet.
-  __ cmp(r2, Operand(Smi::FromInt(0)));
-  __ b(eq, &update_each);
-
   // Convert the entry to a string or (smi) 0 if it isn't a property
   // any more. If the property has been removed while iterating, we
   // just skip it.