Disable pipelining support for non-async routes (#6847)

frameworks/Swift/vapor/vapor-default/Sources/main.swift

@@ -7,6 +7,7 @@ let app = Application(env)
 defer { app.shutdown() }
 
 app.http.server.configuration.serverName = "Vapor"
+app.http.server.configuration.supportPipelining = false
 
 app.logger.notice("💧 VAPOR")
 app.logger.notice("System.coreCount: \(System.coreCount)")