See https://www.illumos.org/issues/14934

--- glib-2.82.0/glib/tests/utf8.txt.orig
+++ glib-2.82.0/glib/tests/utf8.txt
@@ -61,10 +61,6 @@
 VALID
 000007ff
 
-ï¿¿
-VALID
-0000ffff
-
 ÷¿¿¿
 NOTUNICODE
 001fffff
@@ -95,10 +91,6 @@
 VALID
 0010fffd
 
-􏿿
-VALID
-0010ffff
-
 ô€€
 NOTUNICODE
 00110000