[cctest] Deflake CPU profiler tests

Reduce sampling interval to increase test accuracy.
Flakes happen specially when compiling with Sparkplug.

Bug: v8:12054
Change-Id: Ic58bc97d0ad9861259fc8df4b121425b375669e2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3245336
Auto-Submit: Victor Gomes <victorgomes@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77547}

test/cctest/test-cpu-profiler.cc

@@ -571,7 +571,7 @@ v8::CpuProfile* ProfilerHelper::Run(v8::Local<v8::Function> function,
                                     v8::Local<v8::Context> context) {
   v8::Local<v8::String> profile_name = v8_str("my_profile");
 
-  profiler_->SetSamplingInterval(50);
+  profiler_->SetSamplingInterval(20);
   profiler_->StartProfiling(profile_name, {mode, max_samples, 0, context});
 
   v8::internal::CpuProfiler* iprofiler =