Use wpi::span instead of wpi::ArrayRef across all libraries (#3414)

- Remove ArrayRef.h
- Add SpanExtras.h for a couple of convenience functions

wpiutil/src/main/native/cpp/TCPConnector_parallel.cpp

@@ -24,7 +24,7 @@ using namespace wpi;
 #endif
 
 std::unique_ptr<NetworkStream> TCPConnector::connect_parallel(
-    ArrayRef<std::pair<const char*, int>> servers, Logger& logger,
+    span<const std::pair<const char*, int>> servers, Logger& logger,
     int timeout) {
   if (servers.empty()) {
     return nullptr;