fix [#30220] Knife Tool Leaks memory

both crash and leak are fixed now.

source/blender/blenlib/intern/smallhash.c

@@ -88,7 +88,7 @@ void BLI_smallhash_insert(SmallHash *hash, uintptr_t key, void *item)
 		int i = 0;
 
 		if (hash->table != hash->stacktable || newsize > SMSTACKSIZE) {
-			tmp = MEM_callocN(sizeof(*hash->table) * newsize, "new hashkeys");
+			tmp = MEM_callocN(sizeof(*hash->table) * newsize, __func__);
 		}
 		else {
 			SWAP(SmallHashEntry *, hash->stacktable, hash->copytable);

source/blender/editors/mesh/knifetool.c

@@ -1680,6 +1680,8 @@ static void remerge_faces(knifetool_opdata *kcd)
 	/* bm->elem_index_dirty &= ~BM_FACE; */
 	bm->elem_index_dirty |= BM_FACE;
 
+	BLI_smallhash_release(visit);
+
 	BLI_array_free(stack);
 	BLI_array_free(faces);
 }