[builtins] fix builtins PGO gn config and update x64

This is a follow-up to https://chromium-review.googlesource.com/c/v8/v8/+/3776693
The previous CL accidentally didn't manage to enable
the PGO build because `v8_optimized_debug` is true in
release builds.

Bug: v8:10470
Change-Id: I66ec74e71eb697aa48b981d78ad526f4b8c5a917
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3784989
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Auto-Submit: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81971}

BUILD.gn

@@ -449,7 +449,7 @@ if (v8_enable_maglev == "") {
 }
 if (v8_builtins_profiling_log_file == "default") {
   v8_builtins_profiling_log_file = ""
-  if (is_debug == false && v8_optimized_debug == false) {
+  if (is_debug == false) {
     if (v8_current_cpu == "x64") {
       v8_builtins_profiling_log_file = "tools/builtins-pgo/x64.profile"
     }