Fix more -Wsign-compare warnings in heap, mips, base, etc.

src/objects.cc

 // Copyright 2015 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.
 
 #include "src/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <memory>
 #include <sstream>
@@ skipping 20292 matching lines @@
   FetchStarExports(module, &zone, &visited);
   Handle<ObjectHashTable> exports(module->exports(), isolate);
   ZoneVector<Handle<String>> names(&zone);
   names.reserve(exports->NumberOfElements());
   for (int i = 0, n = exports->Capacity(); i < n; ++i) {
     Handle<Object> key(exports->KeyAt(i), isolate);
     if (!exports->IsKey(isolate, *key)) continue;
     DCHECK(exports->ValueAt(i)->IsCell());
     names.push_back(Handle<String>::cast(key));
   }
-  DCHECK_EQ(names.size(), exports->NumberOfElements());
+  DCHECK_EQ(static_cast<int>(names.size()), exports->NumberOfElements());
 
   // Sort them alphabetically.
   struct {
     bool operator()(Handle<String> a, Handle<String> b) {
       return String::Compare(a, b) == ComparisonResult::kLessThan;
     }
   } StringLess;
   std::sort(names.begin(), names.end(), StringLess);
 
   // Create the corresponding properties in the namespace object.
@@ skipping 16 matching lines @@
     // Check if the accessor uses a cached property.
     if (!fti->cached_property_name()->IsTheHole(isolate)) {
       return handle(Name::cast(fti->cached_property_name()));
     }
   }
   return MaybeHandle<Name>();
 }
 
 }  // namespace internal
 }  // namespace v8