tests: Make older linkers happy with one of our test libraries

The linker used in Steam Runtime 1 'scout', which is from several years
ago, doesn't seem to like a symbol being made an alias for a versioned
symbol of the same name. Rename the symbol so that only the versioned
aliases get the same basename.

Signed-off-by: Simon McVittie <smcv@collabora.com>
4 jobs for master in 8 minutes and 23 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
manual #22249
allowed to fail manual
build:arch
passed #22248
build:bionic

00:08:22

passed #22247
build:buster

00:07:16

passed #22246
build:stretch

00:07:45