deps: allow disabling V8 untrusted code mitigations

Add a GYP flag similar to the one defined in BUILD.gn.

PR-URL: #19222
Reviewed-By: Fedor Indutny <fedor.indutny@gmail.com>
Reviewed-By: Yang Guo <yangguo@chromium.org>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Benedikt Meurer <benedikt.meurer@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>

Author: targos

common.gypi

@@ -27,7 +27,7 @@
 
     # 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.4',
+    'v8_embedder_string': '-node.5',
 
     # Enable disassembler for `--print-code` v8 options
     'v8_enable_disassembler': 1,

deps/v8/gypfiles/features.gypi

@@ -89,6 +89,9 @@
 
     # Controls the threshold for on-heap/off-heap Typed Arrays.
     'v8_typed_array_max_size_in_heap%': 64,
+
+    # Enable mitigations for executing untrusted code.
+    'v8_untrusted_code_mitigations%': 'true',
   },
   'target_defaults': {
     'conditions': [
@@ -143,6 +146,9 @@
       ['v8_enable_concurrent_marking==1', {
         'defines': ['V8_CONCURRENT_MARKING',],
       }],
+      ['v8_untrusted_code_mitigations=="false"', {
+        'defines': ['DISABLE_UNTRUSTED_CODE_MITIGATIONS',],
+      }],
     ],  # conditions
     'configurations': {
       'DebugBaseCommon': {