tls: replace var with let and const

PR-URL: #30299
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

lib/_tls_common.js

@@ -91,14 +91,14 @@ exports.SecureContext = SecureContext;
 exports.createSecureContext = function createSecureContext(options) {
   if (!options) options = {};
 
-  var secureOptions = options.secureOptions;
+  let secureOptions = options.secureOptions;
   if (options.honorCipherOrder)
     secureOptions |= SSL_OP_CIPHER_SERVER_PREFERENCE;
 
   const c = new SecureContext(options.secureProtocol, secureOptions,
                               options.minVersion, options.maxVersion);
-  var i;
-  var val;
+  let i;
+  let val;
 
   // Add CA before the cert to be able to load cert's issuer in C++ code.
   const { ca } = options;
@@ -313,7 +313,7 @@ exports.translatePeerCertificate = function translatePeerCertificate(c) {
   }
   if (c.subject != null) c.subject = parseCertString(c.subject);
   if (c.infoAccess != null) {
-    var info = c.infoAccess;
+    const info = c.infoAccess;
     c.infoAccess = Object.create(null);
 
     // XXX: More key validation?