[Intl] Stage Intl.NumberFormat Unified API Proposal

Plan to flip to ship in early June (after m76 branch) for chrome m77.
Spec: https://tc39.github.io/proposal-unified-intl-numberformat/
Design Doc: https://goo.gl/ZAtL1f
I2I: https://groups.google.com/a/chromium.org/forum/?fromgroups#!searchin/blink-dev/Intl%7Csort:date/blink-dev/q3U7sPOG1uo/M7XZU7fxAwAJ

Tests:
intl/number-format/unified/*
test262/intl402/NumberFormat/* (tests with Intl.NumberFormat-unified)

Bug: v8:8515
Change-Id: Ica4108d6ffcc8819940cb6cecb15d852ae7cdf14
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1629407Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61866}

src/flags/flag-definitions.h

@@ -209,9 +209,7 @@ DEFINE_IMPLICATION(harmony_import_meta, harmony_dynamic_import)
   V(harmony_weak_refs, "harmony weak references")
 
 #ifdef V8_INTL_SUPPORT
-#define HARMONY_INPROGRESS(V) \
-  HARMONY_INPROGRESS_BASE(V)  \
-  V(harmony_intl_numberformat_unified, "Unified Intl.NumberFormat Features")
+#define HARMONY_INPROGRESS(V) HARMONY_INPROGRESS_BASE(V)
 #else
 #define HARMONY_INPROGRESS(V) HARMONY_INPROGRESS_BASE(V)
 #endif
@@ -220,10 +218,11 @@ DEFINE_IMPLICATION(harmony_import_meta, harmony_dynamic_import)
 #define HARMONY_STAGED_BASE(V)
 
 #ifdef V8_INTL_SUPPORT
-#define HARMONY_STAGED(V)                                 \
-  HARMONY_STAGED_BASE(V)                                  \
-  V(harmony_intl_add_calendar_numbering_system,           \
-    "Add calendar and numberingSystem to DateTimeFormat") \
+#define HARMONY_STAGED(V)                                                    \
+  HARMONY_STAGED_BASE(V)                                                     \
+  V(harmony_intl_add_calendar_numbering_system,                              \
+    "Add calendar and numberingSystem to DateTimeFormat")                    \
+  V(harmony_intl_numberformat_unified, "Unified Intl.NumberFormat Features") \
   V(harmony_intl_segmenter, "Intl.Segmenter")
 #else
 #define HARMONY_STAGED(V) HARMONY_STAGED_BASE(V)