tools: patch V8 to run on older XCode versions

Patch V8 (compiler/js-heap-broker.cc) to remove the use of an optional
property, which is a fairly new C++ feature, since that requires a newer
XCode version than the minimum requirement in BUILDING.md and thus
breaks CI.

PR-URL: #29694
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Jiawen Geng <technicalcute@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Ujjwal Sharma <usharma1998@gmail.com>

deps/v8/src/compiler/js-heap-broker.cc

@@ -4115,6 +4115,7 @@ GlobalAccessFeedback::GlobalAccessFeedback(PropertyCellRef cell,
 
 GlobalAccessFeedback::GlobalAccessFeedback(FeedbackSlotKind slot_kind)
     : ProcessedFeedback(kGlobalAccess, slot_kind),
+      cell_or_context_(base::nullopt),
       index_and_immutable_(0 /* doesn't matter */) {
   DCHECK(IsGlobalICKind(slot_kind));
 }

deps/v8/src/interpreter/interpreter.cc

@@ -280,7 +280,7 @@ Interpreter::NewSourcePositionCollectionJob(
   auto job = base::make_unique<InterpreterCompilationJob>(parse_info, literal,
                                                           allocator, nullptr);
   job->compilation_info()->SetBytecodeArray(existing_bytecode);
-  return job;
+  return std::unique_ptr<UnoptimizedCompilationJob> { static_cast<UnoptimizedCompilationJob*>(job.release()) };
 }
 
 void Interpreter::ForEachBytecode(