tests: Tolerate greater rendering differences on all non-x86_64

Previously, this used 32-bit vs. 64-bit to discriminate, with
32-bit architectures allowed to deviate more from the reference
rendering (mainly because the i387 FPU used on baseline i386
builds has excess precision in its FP registers). However, one
test also produces a colour channel difference of 3 on
mips64el, a 64-bit architecture; tolerate this too.

Signed-off-by: Simon McVittie <smcv@debian.org>
3 jobs from non-x86-tolerance in 8 minutes and 29 seconds (queued for 6 minutes and 49 seconds)
latest
Status Job ID Name Coverage
  Test
passed #130776
fedora test

00:08:02

 
  Lint
manual #130778
allowed to fail manual
clippy
failed #130777
rustfmt

00:00:26

 
Name Stage Failure
failed
rustfmt Lint
+        let offset = baseline
+ + values
+ .baseline_shift
+ .0
+ .normalize(values, &draw_ctx.get_view_params());

if values.text_gravity_is_vertical() {
draw_ctx.draw_pango_layout(&layout, values, *x + offset, *y, clipping)?;
ERROR: Job failed: exit code 1