Describe the bug
Rotating in 90º increments leaves a black line on one or more sides of non-square images

To Reproduce
Steps to reproduce the behavior:

Using this image:
flip-me-for-real

path = '/path/to/flip-me-for-real.jpg'
img = Vips::Image.new_from_file(path)
img.rotate(90).write_to_file('out90.jpg')

Expected behavior

Expect image to output rotated by 90 degrees without additional image content.

Actual Behavior

actual output out90

Desktop:

• OS: macOS
• Version 12.4
• ruby-vips 2.1.4
• libvips 8.12.2-Tue Jan 25 09:34:32 UTC 2022

** Server **

• heroku-stack 20 (Ubuntu 20.04-based)
• ruby-vips 2.1.4
• libvips 8.12.2-Tue Jan 25 09:34:32 UTC 2022