Pekka Paalanen authored Jun 17, 2022 and Pekka Paalanen committed Jun 30, 2022

The new field in struct scalar_stat allows recording all tested values
into a file. This is intended to replace ad hoc dumping code like in
alpha-blending-test.c.

To make it easy to set up, also offer a helper to open a writable file
whose name consists of a custom prefix and test name.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>