deps: cherry-pick b767cde1e7 from upstream V8

Original commit message:

    [intl] unbreak build with ICU 57

    Remove a call to `icu::toUCharPtr()` that wasn't present in other
    similar looking call sites either, just reinterpret_cast directly.

    Fixes nodejs#19656.

    Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
    Change-Id: If281ce0a39356aa8bd20efb24c3e4b52b06841a3
    Reviewed-on: https://chromium-review.googlesource.com/987953
    Reviewed-by: Daniel Ehrenberg <[email protected]>
    Commit-Queue: Ben Noordhuis <[email protected]>
    Cr-Commit-Position: refs/heads/master@{nodejs#52311}

Fixes: nodejs#19656

deps/v8/src/runtime/runtime-intl.cc

@@ -626,8 +626,7 @@ RUNTIME_FUNCTION(Runtime_PluralRulesSelect) {
   icu::UnicodeString result = plural_rules->select(rounded);
   return *isolate->factory()
               ->NewStringFromTwoByte(Vector<const uint16_t>(
-                  reinterpret_cast<const uint16_t*>(
-                      icu::toUCharPtr(result.getBuffer())),
+                  reinterpret_cast<const uint16_t*>(result.getBuffer()),
                   result.length()))
               .ToHandleChecked();
 }