Chore: add v8-compile-cache to speed up instantiation time

v8-compile-cache attaches a require hook to use V8's code cache to speed up instantiation time.
The "code cache" is the work of parsing and compiling done by V8.

lib/api.js

@@ -5,6 +5,7 @@
 
 "use strict";
 
+require("v8-compile-cache"); // to use V8's code cache to speed up instantiation time
 const { CLIEngine } = require("./cli-engine");
 const { Linter } = require("./linter");
 const { RuleTester } = require("./rule-tester");

package.json

@@ -78,7 +78,8 @@
     "strip-ansi": "^5.2.0",
     "strip-json-comments": "^3.0.1",
     "table": "^5.2.3",
-    "text-table": "^0.2.0"
+    "text-table": "^0.2.0",
+    "v8-compile-cache": "^2.0.3"
   },
   "devDependencies": {
     "@babel/core": "^7.4.3",