[ESNext] Stage optional catch binding

Bug: v8:6889
Change-Id: Ia14a51f4d71059669e62a831c4f3c4d3e60003f1
Reviewed-on: https://chromium-review.googlesource.com/857881Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50464}

src/flag-definitions.h

@@ -207,8 +207,7 @@ DEFINE_IMPLICATION(harmony_class_fields, harmony_static_fields)
   V(harmony_do_expressions, "harmony do-expressions")                 \
   V(harmony_class_fields, "harmony fields in class literals")         \
   V(harmony_static_fields, "harmony static fields in class literals") \
-  V(harmony_bigint, "harmony arbitrary precision integers")           \
-  V(harmony_optional_catch_binding, "allow omitting binding in catch blocks")
+  V(harmony_bigint, "harmony arbitrary precision integers")
 
 // Features that are complete (but still behind --harmony/es-staging flag).
 #define HARMONY_STAGED(V)                                               \
@@ -217,7 +216,8 @@ DEFINE_IMPLICATION(harmony_class_fields, harmony_static_fields)
     "harmony disallow non undefined primitive return value from class " \
     "constructor")                                                      \
   V(harmony_dynamic_import, "harmony dynamic import")                   \
-  V(harmony_public_fields, "harmony public fields in class literals")
+  V(harmony_public_fields, "harmony public fields in class literals")   \
+  V(harmony_optional_catch_binding, "allow omitting binding in catch blocks")
 
 // Features that are shipping (turned on by default, but internal flag remains).
 #define HARMONY_SHIPPING_BASE(V)                                        \