stage2 大量优化代码使其自举编译时间大幅缩短

nob.c

@@ -42,6 +42,8 @@ static const char *splc0_srcs[] = {
     "stage1/spl_ast2ir.c",
     "stage1/spl_layout.c",
     "stage1/spl_ir2vm.c",
+    "stage1/ir_opt.c",
+    "stage1/vm_opt.c",
     "stage0/spl_mcode.c",
 };
 /* clang-format on */