process: create stdin with manualStart: true

Otherwise Node.js will try to read data from the handle.
This causes issues when Node.js is already reading from the
same handle, but a different associated stream
(e.g. a possible IPC channel).

PR-URL: #19377
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/internal/process/stdio.js

@@ -77,13 +77,15 @@ function setupStdio() {
           stdin = new net.Socket({
             handle: process.channel,
             readable: true,
-            writable: false
+            writable: false,
+            manualStart: true
           });
         } else {
           stdin = new net.Socket({
             fd: fd,
             readable: true,
-            writable: false
+            writable: false,
+            manualStart: true
           });
         }
         // Make sure the stdin can't be `.end()`-ed