Add crashing example test

Author: harlanhaskins

Tests/Foundation/TestURLSession.swift

@@ -283,6 +283,16 @@ final class TestURLSession: LoopbackServerTest, @unchecked Sendable {
         await downloadTaskWithRequestAndHandler(with: session)
     }
 
+    func downloadTaskWithTruncatedHeaders() async {
+        let configuration = URLSessionConfiguration.default
+        let session = URLSession(configuration: configuration)
+        let url = URL(string: "https://www.prevention.com/health/a46107400/types-of-magnesium/#")!
+        var request = URLRequest(url: url)
+        request.setValue("facebookexternalhit/1.1", forHTTPHeaderField: "User-Agent")
+
+        let (data, response) = try await session.data(with: url)
+    }
+
     func downloadTaskWithRequestAndHandler(with session: URLSession) async {
         let urlString = "http://127.0.0.1:\(TestURLSession.serverPort)/country.txt"
         let expect = expectation(description: "Download GET \(urlString): with a completion handler")