deps: V8: cherry-pick 0b3a4ecf7083

Original commit message:

    Fix implicit conversion loses integer precision warning

    The type of m is long in 64 bits build, and results implicit conversion
    loses integer precision, which was found by improved clang warning
    (-Wshorten-64-to-32)

    Bug: chromium:1124085
    Change-Id: Ic9f22508bd817a06d5c90162b1ac3554a7171529
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2391323
    Commit-Queue: Zequan Wu <zequanwu@google.com>
    Auto-Submit: Zequan Wu <zequanwu@google.com>
    Reviewed-by: Nico Weber <thakis@chromium.org>
    Reviewed-by: Igor Sheludko <ishell@chromium.org>
    Cr-Commit-Position: refs/heads/master@{#69686}

Refs: v8/v8@0b3a4ec

PR-URL: #39244
Refs: nodejs/build#2696
Reviewed-By: Richard Lau <rlau@redhat.com>

common.gypi

@@ -36,7 +36,7 @@
 
     # Reset this number to 0 on major V8 upgrades.
     # Increment by one for each non-official patch applied to deps/v8.
-    'v8_embedder_string': '-node.70',
+    'v8_embedder_string': '-node.71',
 
     ##### V8 defaults for Node.js #####
 

deps/v8/src/base/macros.h

@@ -339,14 +339,14 @@ inline T RoundDown(T x, intptr_t m) {
   STATIC_ASSERT(std::is_integral<T>::value);
   // m must be a power of two.
   DCHECK(m != 0 && ((m & (m - 1)) == 0));
-  return x & -m;
+  return x & static_cast<T>(-m);
 }
 template <intptr_t m, typename T>
 constexpr inline T RoundDown(T x) {
   STATIC_ASSERT(std::is_integral<T>::value);
   // m must be a power of two.
   STATIC_ASSERT(m != 0 && ((m & (m - 1)) == 0));
-  return x & -m;
+  return x & static_cast<T>(-m);
 }
 
 // Return the smallest multiple of m which is >= x.