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 #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 <littledan@chromium.org>
    Commit-Queue: Ben Noordhuis <info@bnoordhuis.nl>
    Cr-Commit-Position: refs/heads/master@{#52311}

PR-URL: #19710
Fixes: #19656
Refs: v8/v8@b767cde
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Steven R Loomis <srloomis@us.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: bnoordhuis

deps/v8/include/v8-version.h

@@ -11,7 +11,7 @@
 #define V8_MAJOR_VERSION 6
 #define V8_MINOR_VERSION 2
 #define V8_BUILD_NUMBER 414
-#define V8_PATCH_LEVEL 63
+#define V8_PATCH_LEVEL 64
 
 // Use 1 for candidates and 0 otherwise.
 // (Boolean macro values are not supported by all preprocessors.)

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

@@ -631,8 +631,7 @@ 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();
 }