[replaceAll] Stage String.prototype.replaceAll.

Intent to ship thread:
https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/raep1X9R_SE

Bug: v8:9801
Change-Id: I61c559b82b4119084420ffb0a14a27774e37c760
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1930608Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Joshua Litt <joshualitt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65161}

src/flags/flag-definitions.h

@@ -204,7 +204,6 @@ DEFINE_IMPLICATION(harmony_import_meta, harmony_dynamic_import)
 
 // Features that are still work in progress (behind individual flags).
 #define HARMONY_INPROGRESS_BASE(V)                                    \
-  V(harmony_string_replaceall, "harmony String.prototype.replaceAll") \
   V(harmony_regexp_sequence, "RegExp Unicode sequence properties")    \
   V(harmony_weak_refs, "harmony weak references")                     \
   V(harmony_regexp_match_indices, "harmony regexp match indices")     \
@@ -219,7 +218,8 @@ DEFINE_IMPLICATION(harmony_import_meta, harmony_dynamic_import)
 #endif
 
 // Features that are complete (but still behind --harmony/es-staging flag).
-#define HARMONY_STAGED_BASE(V)                                     \
+#define HARMONY_STAGED_BASE(V)                                        \
+  V(harmony_string_replaceall, "harmony String.prototype.replaceAll") \
   V(harmony_private_methods, "harmony private methods in class literals")
 
 #ifdef V8_INTL_SUPPORT