Fix compilation error in builtin-serializer-allocator.cc

Bug: 
Change-Id: I79ddd65af022a22929131fcfc062e15300de04bd
Reviewed-on: https://chromium-review.googlesource.com/732661Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48823}

src/snapshot/builtin-serializer-allocator.cc

@@ -41,7 +41,7 @@ bool BuiltinSerializerAllocator::BackReferenceIsAlreadyAllocated(
 
 std::vector<SerializedData::Reservation>
 BuiltinSerializerAllocator::EncodeReservations() const {
-  return {};
+  return std::vector<SerializedData::Reservation>();
 }
 
 void BuiltinSerializerAllocator::OutputStatistics() {