Issue Description:

In Foundation on Apple platforms, this code works fine:

import Foundation

#if canImport(FoundationNetworking)
import FoundationNetworking
#endif

let task = URLSession.shared
    .dataTask(with: URL(string: "http://www.example.com")!) { data, response, error in
        print("got it")
        exit(EXIT_SUCCESS)
}
    
task.resume()
task.resume()

dispatchMain()

On Linux, however, this causes the following crash:

Fatal error: Resuming a task that's not suspended. Calls to resume() / suspend() need to be matched.: file /home/buildnode/jenkins/workspace/oss-swift-5.1-package-linux-ubuntu-18_04/swift-corelibs-foundation/Foundation/URLSession/URLSessionTask.swift, line 420

This difference causes a crash building the test suite for Alamofire on Linux: Alamofire/Alamofire#3098