deps: V8: cherry-pick 53e62af

Original commit message:

    [build] Include string in v8.h

    Explicitly #include<string> in v8.h, since std::string is referenced
    in it. In the C++ STL shipped with Visual Studio 2019, none of the
    headers included in v8.h ends up including the C++ string header, which
    caused a compile error.

    Bug: v8:9793
    Change-Id: I84a133dd10dd6dcc7b70287af393e82cf0dc97df
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1834321
    Reviewed-by: Adam Klein <adamk@chromium.org>
    Commit-Queue: Adam Klein <adamk@chromium.org>
    Cr-Commit-Position: refs/heads/master@{#64074}

Refs: v8/v8@53e62af

PR-URL: #29898
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Gus Caplan <me@gus.host>

common.gypi

@@ -39,7 +39,7 @@
 
     # 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.13',
+    'v8_embedder_string': '-node.14',
 
     ##### V8 defaults for Node.js #####
 

deps/v8/include/v8.h

@@ -19,6 +19,7 @@
 #include <stdint.h>
 #include <stdio.h>
 #include <memory>
+#include <string>
 #include <type_traits>
 #include <utility>
 #include <vector>