[cpu profiler] Make profiler work even if enabled before isolate creation.

TracingCpuProfiler wrapper uses API interrupt to start the profiling
on the Isolate thread. However it could do it before Isolate is
initialized, so the interrupt it requested got lost.

The patch moves TracingCpuProfiler creation after ThreadLocal object
for isolate is initialized.

BUG=v8:8247

Change-Id: I5b0b3d18e017396f9860faeab909abbfab4616df
Reviewed-on: https://chromium-review.googlesource.com/1252762Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Alexei Filippov <alph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56324}

src/isolate.cc

@@ -2538,8 +2538,6 @@ Isolate::Isolate()
   InitializeLoggingAndCounters();
   debug_ = new Debug(this);
 
-  tracing_cpu_profiler_.reset(new TracingCpuProfilerImpl(this));
-
   init_memcopy_functions();
 
   if (FLAG_embedded_builtins) {
@@ -3011,6 +3009,10 @@ bool Isolate::Init(StartupDeserializer* des) {
 
   InitializeThreadLocal();
 
+  // Profiler has to be created after ThreadLocal is initialized
+  // because it makes use of interrupts.
+  tracing_cpu_profiler_.reset(new TracingCpuProfilerImpl(this));
+
   bootstrapper_->Initialize(create_heap_objects);
 
   if (FLAG_embedded_builtins) {