Revert of Add a trace-event for each runtime-stats timer

src/tracing/trace-event.cc

Index: src/tracing/trace-event.cc
diff --git a/src/tracing/trace-event.cc b/src/tracing/trace-event.cc
index a2c2b830842854316ee81661396bc36c6c91733d..04f1f2e2ea0d0a8df9f504b24954cfc7857cd413 100644
--- a/src/tracing/trace-event.cc
+++ b/src/tracing/trace-event.cc
@@ -10,10 +10,6 @@
 namespace internal {
 namespace tracing {
 
-// A global flag used as a shortcut to check for the
-// v8.runtime category due to its high frequency use.
-int kRuntimeCallsTracingEnabled = 0;
-
 v8::Platform* TraceEventHelper::GetCurrentPlatform() {
   return v8::internal::V8::GetCurrentPlatform();
 }