net: fix pipe inference for adopted non-transport handles

Only trust the adopted handle's type when it came from a BoundSocket;
a TLSSocket's _handle is a TLSWrap, not a Pipe, so TLS/HTTPS over pipes
must still infer pipe-ness from the path option.

Author: guybedford

lib/net.js

@@ -1555,9 +1555,11 @@ Socket.prototype.connect = function(...args) {
   }
 
   const { path } = options;
-  // An adopted handle already fixes the transport; trust its type rather than
-  // inferring pipe-ness from a path option on the connect call.
-  const pipe = this._handle ? this._handle instanceof Pipe : !!path;
+  // An adopted BoundSocket handle already fixes the transport; trust its type
+  // rather than inferring pipe-ness from a path option on the connect call.
+  // Other pre-existing handles (e.g. a TLSWrap) are not transport handles, so
+  // fall back to the path option in that case.
+  const pipe = this[kBoundSource] ? this._handle instanceof Pipe : !!path;
   debug('pipe', pipe, path);
 
   if (!this._handle) {