Turn on icu_case_mapping by default

Update string-capitalize expected result because now it
passes all the tests in the file.
Mark fast/js/string-capitalization as failing with no_i18n.

Relanding after revert because the failure was taken care of
by Adam's CL at https://codereview.chromium.org/2597543002 .

3rd langing after a crash is taken care of in
https://codereview.chromium.org/2621393002

In addition to the previous version of this CL (PS #4) that landed and
reverted, drop String.prototype.to(Locale){Upper,Lower}Case from the
whitelist of built-in functions for side-effect-free-debugging.

BUG=v8:4477, v8:4476
TEST=test262/{built-ins,intl402}/Strings/*, webkit/fast/js/*,
     mjsunit/string-case, intl/general/case*

Cr-Original-Original-Commit-Position: refs/heads/master@{#41834}
Committed: https://chromium.googlesource.com/v8/v8/+/7c79e23c34ea971947eedc6e42d8a882617c0e47
Review-Url: https://codereview.chromium.org/2588963002
Cr-Original-Commit-Position: refs/heads/master@{#41883}
Committed: https://chromium.googlesource.com/v8/v8/+/a42c8c67dece5328896b13d37c5c846a2a0f5b0b
Review-Url: https://codereview.chromium.org/2588963002
Cr-Commit-Position: refs/heads/master@{#42524}

src/flag-definitions.h

@@ -205,7 +205,7 @@ DEFINE_IMPLICATION(es_staging, move_object_start)
   V(harmony_object_rest_spread, "harmony object rest spread properties")
 
 // Features that are complete (but still behind --harmony/es-staging flag).
-#define HARMONY_STAGED_BASE(V)                              \
+#define HARMONY_STAGED(V)                                   \
   V(harmony_regexp_lookbehind, "harmony regexp lookbehind") \
   V(harmony_restrictive_generators,                         \
     "harmony restrictions on generator declarations")       \
@@ -213,21 +213,14 @@ DEFINE_IMPLICATION(es_staging, move_object_start)
   V(harmony_trailing_commas,                                \
     "harmony trailing commas in function parameter lists")
 
-#ifdef V8_I18N_SUPPORT
-#define HARMONY_STAGED(V)                                          \
-  HARMONY_STAGED_BASE(V)                                           \
-  V(icu_case_mapping, "case mapping with ICU rather than Unibrow")
-#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)
 
 #ifdef V8_I18N_SUPPORT
-#define HARMONY_SHIPPING(V) \
-  HARMONY_SHIPPING_BASE(V)  \
-  V(datetime_format_to_parts, "Intl.DateTimeFormat.formatToParts")
+#define HARMONY_SHIPPING(V)                                        \
+  HARMONY_SHIPPING_BASE(V)                                         \
+  V(datetime_format_to_parts, "Intl.DateTimeFormat.formatToParts") \
+  V(icu_case_mapping, "case mapping with ICU rather than Unibrow")
 #else
 #define HARMONY_SHIPPING(V) HARMONY_SHIPPING_BASE(V)
 #endif

test/debugger/debug/debug-evaluate-no-side-effect-builtins.js

@@ -46,7 +46,10 @@ function listener(event, exec_state, event_data, data) {
     for (f of Object.getOwnPropertyNames(String.prototype)) {
       if (typeof String.prototype[f] === "function") {
         // Do not expect locale-specific or regexp-related functions to work.
+        // {Lower,Upper}Case (Locale-specific or not) do not work either.
         if (f.indexOf("locale") >= 0) continue;
+        if (f.indexOf("Lower") >= 0) continue;
+        if (f.indexOf("Upper") >= 0) continue;
         if (f == "normalize") continue;
         if (f == "match") continue;
         if (f == "search") continue;
@@ -54,6 +57,10 @@ function listener(event, exec_state, event_data, data) {
         success("abcd"[f](2), `"abcd".${f}(2);`);
       }
     }
+    fail("'abCd'.toLowerCase()");
+    fail("'abcd'.toUpperCase()");
+    fail("'abCd'.toLocaleLowerCase()");
+    fail("'abcd'.toLocaleUpperCase()");
     fail("'abcd'.match(/a/)");
     fail("'abcd'.replace(/a/)");
     fail("'abcd'.search(/a/)");

test/webkit/fast/js/string-capitalization-expected.txt

@@ -26,8 +26,8 @@ This test checks that toLowerCase and toUpperCase handle certain non-trivial cas
 On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
 
 
-FAIL String("A𐐀").toLowerCase() should be a𐐨. Was a𐐀.
-FAIL String("a𐐨").toUpperCase() should be A𐐀. Was A𐐨.
+PASS String("A𐐀").toLowerCase() is "a𐐨"
+PASS String("a𐐨").toUpperCase() is "A𐐀"
 PASS String("ΚΟΣΜΟΣ ΚΟΣΜΟΣ").toLowerCase() is "κοσμος κοσμος"
 PASS String("ß").toUpperCase() is "SS"
 PASS String("ʼn").toUpperCase() is "ʼN"

test/webkit/webkit.status

@@ -125,5 +125,10 @@
   '*': [SKIP],
 }],  # variant == wasm_traps
 
+##############################################################################
+['no_i18n == True', {
+  'fast/js/string-capitalization': [FAIL],
+}],  # variant == wasm_traps
+
 ##############################################################################
 ]