stream: drain Transform with 0 highWaterMark

Fixes: #40935

PR-URL: #40947
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

Author: ronag

lib/internal/streams/transform.js

@@ -196,6 +196,7 @@ Transform.prototype._write = function(chunk, encoding, callback) {
       wState.ended || // Backwards compat.
       length === rState.length || // Backwards compat.
       rState.length < rState.highWaterMark ||
+      rState.highWaterMark === 0 ||
       rState.length === 0
     ) {
       callback();

test/parallel/test-stream-passthrough-drain.js

@@ -0,0 +1,8 @@
+'use strict';
+const common = require('../common');
+const { PassThrough } = require('stream');
+
+const pt = new PassThrough({ highWaterMark: 0 });
+pt.on('drain', common.mustCall());
+pt.write('hello');
+pt.read();