[Intl] Stage Intl.Segmenter

This will give us some clusterfuzz coverage.

Bug: v8:6891
Change-Id: I167774aeb0110bde8d5ed1047b2875b14317903b
Reviewed-on: https://chromium-review.googlesource.com/c/1301643Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57099}

src/flag-definitions.h

@@ -203,18 +203,25 @@ DEFINE_IMPLICATION(harmony_class_fields, harmony_private_fields)
 #define HARMONY_INPROGRESS(V)                    \
   HARMONY_INPROGRESS_BASE(V)                     \
   V(harmony_locale, "Intl.Locale")               \
-  V(harmony_intl_list_format, "Intl.ListFormat") \
-  V(harmony_intl_segmenter, "Intl.Segmenter")
+  V(harmony_intl_list_format, "Intl.ListFormat")
 #else
 #define HARMONY_INPROGRESS(V) HARMONY_INPROGRESS_BASE(V)
 #endif
 
 // Features that are complete (but still behind --harmony/es-staging flag).
-#define HARMONY_STAGED(V)                                                  \
+#define HARMONY_STAGED_BASE(V)                                             \
   V(harmony_private_fields, "harmony private fields in class literals")    \
   V(harmony_numeric_separator, "harmony numeric separator between digits") \
   V(harmony_string_matchall, "harmony String.prototype.matchAll")
 
+#ifdef V8_INTL_SUPPORT
+#define HARMONY_STAGED(V) \
+  HARMONY_STAGED_BASE(V)  \
+  V(harmony_intl_segmenter, "Intl.Segmenter")
+#else
+#define HARMONY_STAGED(V) HARMONY_STAGED_BASE(V)
+#endif
+
 // Features that are shipping (turned on by default, but internal flag remains).
 #define HARMONY_SHIPPING_BASE(V)                                               \
   V(harmony_namespace_exports,                                                 \