Fabric: Using `unordered_map` instead of `map` for RawProps

Summary:
@public
We don't need to maintain an order of this collection, so using `unordered_map` is more appropriate.

Reviewed By: mdvacca

Differential Revision: D8826946

fbshipit-source-id: f6890097cc5d6a1e06f6b2cfd1b7d68a388da461

ReactCommon/fabric/core/primitives/ReactPrimitives.h

@@ -9,6 +9,7 @@
 
 #include <memory>
 #include <string>
+#include <unordered_map>
 
 #include <folly/dynamic.h>
 
@@ -25,7 +26,7 @@ using InstanceHandle = struct InstanceHandleDummyStruct {} *;
  * `RawProps` represents untyped map with props comes from JavaScript side.
  */
 // TODO(T26954420): Use iterator as underlying type for RawProps.
-using RawProps = std::map<std::string, folly::dynamic>;
+using RawProps = std::unordered_map<std::string, folly::dynamic>;
 using SharedRawProps = std::shared_ptr<const RawProps>;
 
 /*