[9.18] fix: test: Various coccinelle fixes

Backport of MR !9836

Merge branch 'backport-mnowak/cocci-more-set-if-not-null-changes-9.18' into 'bind-9.18'

See merge request isc-projects/bind9!9917

tests/libtest/ns.c

@@ -400,15 +400,9 @@ extract_qctx(void *arg, void *data, isc_result_t *resultp) {
 	 * gets unwound.
 	 */
 	qctx = isc_mem_get(mctx, sizeof(*qctx));
-	if (qctx != NULL) {
-		memmove(qctx, (query_ctx_t *)arg, sizeof(*qctx));
-	}
+	memmove(qctx, (query_ctx_t *)arg, sizeof(*qctx));
 
 	qctxp = (query_ctx_t **)data;
-	/*
-	 * If memory allocation failed, the supplied pointer will simply be set
-	 * to NULL.  We rely on the user of this hook to react properly.
-	 */
 	*qctxp = qctx;
 	*resultp = ISC_R_UNSET;