Serializer: another small reorder of root objects.

I was mistaken, cons strings only occur a lot for custom heap snapshots,
not for the default start-up snapshot.

R=erik.corry@gmail.com, mvstanton@chromium.org

Review URL: https://codereview.chromium.org/1023673003

Cr-Commit-Position: refs/heads/master@{#27312}

src/heap/heap.h

@@ -54,7 +54,7 @@ namespace internal {
   V(Map, weak_cell_map, WeakCellMap)                                           \
   V(Map, one_byte_string_map, OneByteStringMap)                                \
   V(Map, one_byte_internalized_string_map, OneByteInternalizedStringMap)       \
-  V(Map, cons_one_byte_string_map, ConsOneByteStringMap)                       \
+  V(Map, function_context_map, FunctionContextMap)                             \
   V(FixedArray, empty_fixed_array, EmptyFixedArray)                            \
   V(ByteArray, empty_byte_array, EmptyByteArray)                               \
   V(DescriptorArray, empty_descriptor_array, EmptyDescriptorArray)             \
@@ -78,6 +78,7 @@ namespace internal {
   V(Map, ordered_hash_table_map, OrderedHashTableMap)                          \
   V(Map, symbol_map, SymbolMap)                                                \
   V(Map, string_map, StringMap)                                                \
+  V(Map, cons_one_byte_string_map, ConsOneByteStringMap)                       \
   V(Map, cons_string_map, ConsStringMap)                                       \
   V(Map, sliced_string_map, SlicedStringMap)                                   \
   V(Map, sliced_one_byte_string_map, SlicedOneByteStringMap)                   \
@@ -141,7 +142,6 @@ namespace internal {
   V(FixedTypedArrayBase, empty_fixed_uint8_clamped_array,                      \
     EmptyFixedUint8ClampedArray)                                               \
   V(Map, sloppy_arguments_elements_map, SloppyArgumentsElementsMap)            \
-  V(Map, function_context_map, FunctionContextMap)                             \
   V(Map, catch_context_map, CatchContextMap)                                   \
   V(Map, with_context_map, WithContextMap)                                     \
   V(Map, block_context_map, BlockContextMap)                                   \