Fix StringBase_createFromCodePoints to correctly accept Latin-1 characters

lib/string.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/bootstrap_natives.h"
 
 #include "vm/exceptions.h"
 #include "vm/native_entry.h"
 #include "vm/object.h"
 #include "vm/symbols.h"
@@ skipping 16 matching lines @@
     if (!index_object.IsSmi()) {
       GrowableArray<const Object*> args;
       args.Add(&index_object);
       Exceptions::ThrowByType(Exceptions::kArgument, args);
     }
     intptr_t value = Smi::Cast(index_object).Value();
     if (value < 0) {
       GrowableArray<const Object*> args;
       Exceptions::ThrowByType(Exceptions::kArgument, args);
     } else {
-      if (value > 0x7F) {
+      if (value > 0xFF) {
         is_one_byte_string = false;
       }
       if (value > 0xFFFF) {
         utf16_len += 1;
       }
     }
     utf32_array[i] = value;
   }
   if (is_one_byte_string) {
     return OneByteString::New(utf32_array, array_len, Heap::kNew);
@@ skipping 99 matching lines @@
     if (!elem.IsString()) {
       GrowableArray<const Object*> args;
       args.Add(&elem);
       Exceptions::ThrowByType(Exceptions::kArgument, args);
     }
   }
   return String::ConcatAll(strings);
 }
 
 }  // namespace dart