[maglev] Allow the optimizer with --maglev --no-opt

This will need re-work but it allows us to test for now.

Bug: v8:7700
Change-Id: I4eabb7f9f8e8a4c0d23c6bab22c7f0127c7820dd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3579102
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79873}

src/execution/isolate.cc

@@ -4356,8 +4356,8 @@ CodeTracer* Isolate::GetCodeTracer() {
 
 bool Isolate::use_optimizer() {
   // TODO(v8:7700): Update this predicate for a world with multiple tiers.
-  return FLAG_opt && !serializer_enabled_ && CpuFeatures::SupportsOptimizer() &&
-         !is_precise_count_code_coverage();
+  return (FLAG_opt || FLAG_maglev) && !serializer_enabled_ &&
+         CpuFeatures::SupportsOptimizer() && !is_precise_count_code_coverage();
 }
 
 void Isolate::IncreaseTotalRegexpCodeGenerated(Handle<HeapObject> code) {