crypto: make _toBuf non-enumerable

Refs: nodejs#22501
Refs: nodejs#22519

Author: tniessen

lib/crypto.js

@@ -137,7 +137,6 @@ function createVerify(algorithm, options) {
 
 module.exports = exports = {
   // Methods
-  _toBuf: deprecate(toBuf, 'crypto._toBuf is deprecated.', 'DEP0114'),
   createCipheriv,
   createDecipheriv,
   createDiffieHellman,
@@ -205,6 +204,10 @@ function getFipsForced() {
 }
 
 Object.defineProperties(exports, {
+  _toBuf: {
+    enumerable: false,
+    value: deprecate(toBuf, 'crypto._toBuf is deprecated.', 'DEP0114')
+  },
   createCipher: {
     enumerable: false,
     value: deprecate(createCipher,