lib: make c, ca and certs const in _tls_common

PR-URL: #20073
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/_tls_common.js

@@ -88,15 +88,15 @@ exports.createSecureContext = function createSecureContext(options, context) {
   if (options.honorCipherOrder)
     secureOptions |= SSL_OP_CIPHER_SERVER_PREFERENCE;
 
-  var c = new SecureContext(options.secureProtocol, secureOptions, context);
+  const c = new SecureContext(options.secureProtocol, secureOptions, context);
   var i;
   var val;
 
   if (context) return c;
 
   // NOTE: It's important to add CA before the cert to be able to load
   // cert's issuer in C++ code.
-  var ca = options.ca;
+  const { ca } = options;
   if (ca) {
     if (Array.isArray(ca)) {
       for (i = 0; i < ca.length; ++i) {
@@ -112,7 +112,7 @@ exports.createSecureContext = function createSecureContext(options, context) {
     c.context.addRootCerts();
   }
 
-  var cert = options.cert;
+  const { cert } = options;
   if (cert) {
     if (Array.isArray(cert)) {
       for (i = 0; i < cert.length; ++i) {