Serializer: reorder root list items.

The first 32 root list items can be encoded very efficiently.
By reordering, we can better encode some often referenced root objects.

R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/1019243002

Cr-Commit-Position: refs/heads/master@{#27293}

src/heap/heap.h

@@ -38,7 +38,6 @@ namespace internal {
   V(Oddball, true_value, TrueValue)                                            \
   V(Oddball, false_value, FalseValue)                                          \
   V(Oddball, uninitialized_value, UninitializedValue)                          \
-  V(Oddball, exception, Exception)                                             \
   V(Map, cell_map, CellMap)                                                    \
   V(Map, global_property_cell_map, GlobalPropertyCellMap)                      \
   V(Map, shared_function_info_map, SharedFunctionInfoMap)                      \
@@ -53,17 +52,20 @@ namespace internal {
   V(Map, fixed_double_array_map, FixedDoubleArrayMap)                          \
   V(Map, constant_pool_array_map, ConstantPoolArrayMap)                        \
   V(Map, weak_cell_map, WeakCellMap)                                           \
-  V(Oddball, no_interceptor_result_sentinel, NoInterceptorResultSentinel)      \
-  V(Map, hash_table_map, HashTableMap)                                         \
-  V(Map, ordered_hash_table_map, OrderedHashTableMap)                          \
+  V(Map, one_byte_string_map, OneByteStringMap)                                \
+  V(Map, one_byte_internalized_string_map, OneByteInternalizedStringMap)       \
+  V(Map, cons_one_byte_string_map, ConsOneByteStringMap)                       \
   V(FixedArray, empty_fixed_array, EmptyFixedArray)                            \
   V(ByteArray, empty_byte_array, EmptyByteArray)                               \
   V(DescriptorArray, empty_descriptor_array, EmptyDescriptorArray)             \
   V(ConstantPoolArray, empty_constant_pool_array, EmptyConstantPoolArray)      \
-  V(Oddball, arguments_marker, ArgumentsMarker)                                \
   /* The roots above this line should be boring from a GC point of view.    */ \
   /* This means they are never in new space and never on a page that is     */ \
   /* being compacted.                                                       */ \
+  V(Oddball, no_interceptor_result_sentinel, NoInterceptorResultSentinel)      \
+  V(Oddball, arguments_marker, ArgumentsMarker)                                \
+  V(Oddball, exception, Exception)                                             \
+  V(Oddball, termination_exception, TerminationException)                      \
   V(FixedArray, number_string_cache, NumberStringCache)                        \
   V(Object, instanceof_cache_function, InstanceofCacheFunction)                \
   V(Object, instanceof_cache_map, InstanceofCacheMap)                          \
@@ -71,13 +73,12 @@ namespace internal {
   V(FixedArray, single_character_string_cache, SingleCharacterStringCache)     \
   V(FixedArray, string_split_cache, StringSplitCache)                          \
   V(FixedArray, regexp_multiple_cache, RegExpMultipleCache)                    \
-  V(Oddball, termination_exception, TerminationException)                      \
   V(Smi, hash_seed, HashSeed)                                                  \
+  V(Map, hash_table_map, HashTableMap)                                         \
+  V(Map, ordered_hash_table_map, OrderedHashTableMap)                          \
   V(Map, symbol_map, SymbolMap)                                                \
   V(Map, string_map, StringMap)                                                \
-  V(Map, one_byte_string_map, OneByteStringMap)                                \
   V(Map, cons_string_map, ConsStringMap)                                       \
-  V(Map, cons_one_byte_string_map, ConsOneByteStringMap)                       \
   V(Map, sliced_string_map, SlicedStringMap)                                   \
   V(Map, sliced_one_byte_string_map, SlicedOneByteStringMap)                   \
   V(Map, external_string_map, ExternalStringMap)                               \
@@ -89,7 +90,6 @@ namespace internal {
   V(Map, short_external_string_with_one_byte_data_map,                         \
     ShortExternalStringWithOneByteDataMap)                                     \
   V(Map, internalized_string_map, InternalizedStringMap)                       \
-  V(Map, one_byte_internalized_string_map, OneByteInternalizedStringMap)       \
   V(Map, external_internalized_string_map, ExternalInternalizedStringMap)      \
   V(Map, external_internalized_string_with_one_byte_data_map,                  \
     ExternalInternalizedStringWithOneByteDataMap)                              \