SDL_image: test: Increase tolerance of JXL decoding

SDL Commits
1 
From 092cdc93cda20be0962b2eee4573ad0ac24986f6 Mon Sep 17 00:00:00 2001
From: Simon McVittie <[EMAIL REDACTED]>
Date: Mon, 23 May 2022 18:00:36 +0100
Subject: [PATCH] test: Increase tolerance of JXL decoding

When running the tests with vendored libjxl, the results were visually
indistinguishable from the reference image, but with more difference
than our previous arbitrary limit (sum of squares of colour channels
<= 100). Raise the arbitrary limit to 300.

Fixes: 59dff46 "Add a simple automated test"
Signed-off-by: Simon McVittie <smcv@collabora.com>
---
 test/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/main.c b/test/main.c
index 559ccfe..bf94395 100644
--- a/test/main.c
+++ b/test/main.c
@@ -241,7 +241,7 @@ static const Format formats[] =
         "sample.bmp",
         23,
         42,
-        100,
+        300,
         IMG_INIT_JXL,
 #ifdef LOAD_JXL
         SDL_TRUE,