test: clip the exit code to 255

If more than 255 tests fail, we're returning an exit code outside of the POSIX
standard. This only takes effect for -j1, where we fork off we only ever have
a failed value of 1 anyway.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

test/litest.c

@@ -4100,6 +4100,6 @@ main(int argc, char **argv)
 #endif
 	}
 
-	return failed_tests;
+	return min(failed_tests, 255);
 }
 #endif