Fabric: Using thread_local keyword instead on own implementation in TransactionTelemetry

Summary:
Apparently, there is C++ keyword for this.

Changelog: [Internal] Fabric-specific internal change.

Reviewed By: sammy-SC

Differential Revision: D23754284

fbshipit-source-id: 5f9bbcc72d9c586173624869d614f12d2319fb7b

Author: shergin

ReactCommon/react/renderer/mounting/TransactionTelemetry.cpp

@@ -12,18 +12,18 @@
 namespace facebook {
 namespace react {
 
-using ThreadLocalTransactionTelemetry = ThreadStorage<TransactionTelemetry *>;
+thread_local TransactionTelemetry *threadLocalTransactionTelemetry = nullptr;
 
 TransactionTelemetry *TransactionTelemetry::threadLocalTelemetry() {
-  return ThreadLocalTransactionTelemetry::getInstance().get().value_or(nullptr);
+  return threadLocalTransactionTelemetry;
 }
 
 void TransactionTelemetry::setAsThreadLocal() {
-  ThreadLocalTransactionTelemetry::getInstance().set(this);
+  threadLocalTransactionTelemetry = this;
 }
 
 void TransactionTelemetry::unsetAsThreadLocal() {
-  ThreadLocalTransactionTelemetry::getInstance().set(nullptr);
+  threadLocalTransactionTelemetry = nullptr;
 }
 
 void TransactionTelemetry::willCommit() {

ReactCommon/react/renderer/mounting/TransactionTelemetry.h

@@ -11,7 +11,6 @@
 #include <cstdint>
 
 #include <react/utils/Telemetry.h>
-#include <react/utils/ThreadStorage.h>
 
 namespace facebook {
 namespace react {