Revert "fs: fix options.end of fs.ReadStream()"

This reverts commit b343cb6.

Some people were relying on the behavior of this.start being able to be
undefined, whereas after the change it is being set to 0.

Refs: nodejs#19240
Refs: nodejs#18121

lib/fs.js

@@ -1950,8 +1950,7 @@ function ReadStream(path, options) {
   this.flags = options.flags === undefined ? 'r' : options.flags;
   this.mode = options.mode === undefined ? 0o666 : options.mode;
 
-  this.start = typeof this.fd !== 'number' && options.start === undefined ?
-    0 : options.start;
+  this.start = options.start;
   this.end = options.end;
   this.autoClose = options.autoClose === undefined ? true : options.autoClose;
   this.pos = undefined;

test/parallel/test-fs-read-stream.js

@@ -157,20 +157,6 @@ assert.throws(function() {
   }));
 }
 
-{
-  // Verify that end works when start is not specified.
-  const stream = new fs.createReadStream(rangeFile, { end: 1 });
-  stream.data = '';
-
-  stream.on('data', function(chunk) {
-    stream.data += chunk;
-  });
-
-  stream.on('end', common.mustCall(function() {
-    assert.strictEqual('xy', stream.data);
-  }));
-}
-
 {
   // pause and then resume immediately.
   const pauseRes = fs.createReadStream(rangeFile);