Stage restrictive declarations flag

This flag bans illegal (and likely useless) constructs like

for (;;) function f() {}

R=adamk
BUG=v8:4824
LOG=Y

Review URL: https://codereview.chromium.org/1781653005

Cr-Commit-Position: refs/heads/master@{#34646}

src/flag-definitions.h

@@ -212,9 +212,7 @@ DEFINE_IMPLICATION(es_staging, harmony_tailcalls)
   V(harmony_simd, "harmony simd")                                       \
   V(harmony_do_expressions, "harmony do-expressions")                   \
   V(harmony_tailcalls, "harmony tail calls")                            \
-  V(harmony_regexp_property, "harmony unicode regexp property classes") \
-  V(harmony_restrictive_declarations,                                   \
-    "harmony limitations on sloppy mode function declarations")
+  V(harmony_regexp_property, "harmony unicode regexp property classes")
 
 // Features that are complete (but still behind --harmony/es-staging flag).
 #define HARMONY_STAGED(V)                                                    \
@@ -223,7 +221,9 @@ DEFINE_IMPLICATION(es_staging, harmony_tailcalls)
   V(harmony_instanceof, "harmony instanceof support")                        \
   V(harmony_object_values_entries, "harmony Object.values / Object.entries") \
   V(harmony_object_own_property_descriptors,                                 \
-    "harmony Object.getOwnPropertyDescriptors()")
+    "harmony Object.getOwnPropertyDescriptors()")                            \
+  V(harmony_restrictive_declarations,                                        \
+    "harmony limitations on sloppy mode function declarations")
 
 // Features that are shipping (turned on by default, but internal flag remains).
 #define HARMONY_SHIPPING(V)                                               \