http2: use writableFinished instead of _writableState

PR-URL: #28007
Refs: #445
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Rich Trott <rtrott@gmail.com>

lib/internal/http2/core.js

@@ -1556,7 +1556,7 @@ function closeStream(stream, code, rstStreamStatus = kSubmitRstStream) {
   stream.setTimeout(0);
   stream.removeAllListeners('timeout');
 
-  const { ending, finished } = stream._writableState;
+  const { ending } = stream._writableState;
 
   if (!ending) {
     // If the writable side of the Http2Stream is still open, emit the
@@ -1572,7 +1572,7 @@ function closeStream(stream, code, rstStreamStatus = kSubmitRstStream) {
 
   if (rstStreamStatus !== kNoRstStream) {
     const finishFn = finishCloseStream.bind(stream, code);
-    if (!ending || finished || code !== NGHTTP2_NO_ERROR ||
+    if (!ending || stream.writableFinished || code !== NGHTTP2_NO_ERROR ||
         rstStreamStatus === kForceRstStream)
       finishFn();
     else
@@ -1982,8 +1982,7 @@ class Http2Stream extends Duplex {
       return;
     }
 
-    // TODO(mcollina): remove usage of _*State properties
-    if (this._writableState.finished) {
+    if (this.writableFinished) {
       if (!this.readable && this.closed) {
         this.destroy();
         return;