Merge pull request #21678 from grpc/revert-21661-odrsidestep

Revert "Sidestep multiple initialization issue of Tracers with Makefile"

src/core/lib/debug/trace.cc

@@ -70,14 +70,6 @@ bool TraceFlagList::Set(const char* name, bool enabled) {
 }
 
 void TraceFlagList::Add(TraceFlag* flag) {
-  // TODO(yashykt): This loop is present to sidestep
-  // https://github.com/grpc/grpc/issues/21213. Remove it when either Makefile
-  // is fixed, or it's deprecated.
-  for (TraceFlag* t = root_tracer_; t != nullptr; t = t->next_tracer_) {
-    if (t == flag) {
-      return;
-    }
-  }
   flag->next_tracer_ = root_tracer_;
   root_tracer_ = flag;
 }