[esnext] ship Object.getOwnPropertyDescriptors

Flip the --harmony_object_own_property_descriptors flag to enabled by default.

Intent-to-Ship at https://groups.google.com/forum/#!topic/v8-users/xhTKRuY0_V8

BUG=v8:4725
R=adamk@chromium.org, littledan@chromium.org

Review-Url: https://codereview.chromium.org/2191023002
Cr-Commit-Position: refs/heads/master@{#38181}

src/flag-definitions.h

@@ -216,8 +216,6 @@ DEFINE_IMPLICATION(es_staging, move_object_start)
 #define HARMONY_STAGED_BASE(V)                                               \
   V(harmony_regexp_lookbehind, "harmony regexp lookbehind")                  \
   V(harmony_tailcalls, "harmony tail calls")                                 \
-  V(harmony_object_own_property_descriptors,                                 \
-    "harmony Object.getOwnPropertyDescriptors()")                            \
   V(harmony_async_await, "harmony async-await")                              \
   V(harmony_string_padding, "harmony String-padding methods")
 
@@ -234,7 +232,9 @@ DEFINE_IMPLICATION(es_staging, move_object_start)
   V(harmony_restrictive_declarations,                                        \
     "harmony limitations on sloppy mode function declarations")              \
   V(harmony_exponentiation_operator, "harmony exponentiation operator `**`") \
-  V(harmony_object_values_entries, "harmony Object.values / Object.entries")
+  V(harmony_object_values_entries, "harmony Object.values / Object.entries") \
+  V(harmony_object_own_property_descriptors,                                 \
+    "harmony Object.getOwnPropertyDescriptors()")
 
 // Once a shipping feature has proved stable in the wild, it will be dropped
 // from HARMONY_SHIPPING, all occurrences of the FLAG_ variable are removed,