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/alloc.c b/src/alloc.c
index fa92c56..5f39085 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -226,7 +226,7 @@
     {
 	// Don't hide this message
 	emsg_silent = 0;
-	iemsg(_(e_internal_error_lalloc_zero));
+	iemsg(e_internal_error_lalloc_zero);
 	return NULL;
     }