Ship --harmony_array_includes

Intent to ship: https://groups.google.com/d/msg/v8-users/-a8_8cb6FRI/trjyB5bACQAJ

BUG=v8:3575
R=adamk@chromium.org, rossberg@chromium.org
LOG=Y
CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:linux_chromium_rel_ng;tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1295543003

Cr-Commit-Position: refs/heads/master@{#30339}

src/flag-definitions.h

@@ -205,7 +205,6 @@ DEFINE_BOOL(legacy_const, true, "legacy semantics for const in sloppy mode")
 // Features that are complete (but still behind --harmony/es-staging flag).
 #define HARMONY_STAGED(V)                                       \
   V(harmony_arrow_functions, "harmony arrow functions")         \
-  V(harmony_array_includes, "harmony Array.prototype.includes") \
   V(harmony_tostring, "harmony toString")                       \
   V(harmony_concat_spreadable, "harmony isConcatSpreadable")    \
   V(harmony_rest_parameters, "harmony rest parameters")         \
@@ -213,6 +212,7 @@ DEFINE_BOOL(legacy_const, true, "legacy semantics for const in sloppy mode")
 
 // Features that are shipping (turned on by default, but internal flag remains).
 #define HARMONY_SHIPPING(V)                                     \
+  V(harmony_array_includes, "harmony Array.prototype.includes") \
   V(harmony_new_target, "harmony new.target")                   \
   V(harmony_object_observe, "harmony Object.observe")           \
   V(harmony_spreadcalls, "harmony spread-calls")                \