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

src/full-codegen/arm64/full-codegen-arm64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_ARM64
 
 #include "src/ast/scopes.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 1120 matching lines @@
   __ Peek(x2, 3 * kXRegSize);
 
   // Check if the expected map still matches that of the enumerable.
   // If not, we may have to filter the key.
   Label update_each;
   __ Peek(x1, 4 * kXRegSize);
   __ Ldr(x11, FieldMemOperand(x1, HeapObject::kMapOffset));
   __ Cmp(x11, x2);
   __ B(eq, &update_each);
 
-  // For proxies, no filtering is done.
-  // TODO(rossberg): What if only a prototype is a proxy? Not specified yet.
-  STATIC_ASSERT(kSmiTag == 0);
-  __ Cbz(x2, &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.
   __ Push(x1, x3);
   __ CallRuntime(Runtime::kForInFilter, 2);
   PrepareForBailoutForId(stmt->FilterId(), TOS_REG);
   __ Mov(x3, x0);
   __ JumpIfRoot(x0, Heap::kUndefinedValueRootIndex,
                 loop_statement.continue_label());
 
@@ skipping 3778 matching lines @@
   }
 
   return INTERRUPT;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM64