buffer: fix creating from zero-length ArrayBuffer

Fixes regression where creating a new Buffer from an
empty ArrayBuffer would fail.

Ref: 85ab4a5f12
PR-URL: https://github.com/nodejs/node/pull/7176
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Сковорода Никита Андреевич <chalkerx@gmail.com>
Reviewed-By: Ron Korving <ron@ronkorving.nl>

lib/buffer.js

@@ -257,7 +257,7 @@ function fromArrayBuffer(obj, byteOffset, length) {
 
   const maxLength = obj.byteLength - byteOffset;
 
-  if (maxLength <= 0)
+  if (maxLength < 0)
     throw new RangeError("'offset' is out of bounds");
 
   if (length === undefined) {

test/parallel/test-buffer-alloc.js

@@ -1459,3 +1459,8 @@ const ubuf = Buffer.allocUnsafeSlow(10);
 assert(ubuf);
 assert(ubuf.buffer);
 assert.equal(ubuf.buffer.byteLength, 10);
+
+// Regression test
+assert.doesNotThrow(() => {
+  Buffer.from(new ArrayBuffer());
+});