patch 9.0.1594: some internal error messages are translated

Problem:    Some internal error messages are translated.
Solution:   Consistently do not translate internal error messages.
            (closes #12459)
diff --git a/src/textprop.c b/src/textprop.c
index c6464fc..e8ccfe1 100644
--- a/src/textprop.c
+++ b/src/textprop.c
@@ -642,7 +642,7 @@
 	return 0;
     if (proplen % sizeof(textprop_T) != 0)
     {
-	iemsg(_(e_text_property_info_corrupted));
+	iemsg(e_text_property_info_corrupted);
 	return 0;
     }
     *props = text + textlen;