crypto: fix misleading positional argument

The fourth positional argument of `createCipherBase` is `true` when
called from within the `Cipheriv` constructor and `false`when called
from within the `Decipheriv` constructor. This value is then passed to
the `CipherBase::New()` method, which treats it as follows:
args[0]->IsTrue() ? kCipher : kDecipher
However, the current name of said positional argument is `decipher` and
thus indicates the exact opposite: when the argument is set to true, the
instance is *not* a `Decipheriv` object. Therefore, this commit renames
the argument to `isEncrypt`, which matches the actual semantics.
PR-URL: #57843
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Edy Silva <edigleyssonsilva@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: tniessen

lib/internal/crypto/cipher.js

@@ -112,21 +112,21 @@ function getUIntOption(options, key) {
 return-1;
 }
 
-functioncreateCipherBase(cipher,credential,options,decipher,iv){
+functioncreateCipherBase(cipher,credential,options,isEncrypt,iv){
 constauthTagLength=getUIntOption(options,'authTagLength');
-this[kHandle]=newCipherBase(decipher);
+this[kHandle]=newCipherBase(isEncrypt);
 this[kHandle].initiv(cipher,credential,iv,authTagLength);
 this._decoder=null;
 
 ReflectApply(LazyTransform,this,[options]);
 }
 
-functioncreateCipherWithIV(cipher,key,options,decipher,iv){
+functioncreateCipherWithIV(cipher,key,options,isEncrypt,iv){
 validateString(cipher,'cipher');
 constencoding=getStringOption(options,'encoding');
 key=prepareSecretKey(key,encoding);
 iv=iv===null ? null : getArrayBufferOrView(iv,'iv');
-ReflectApply(createCipherBase,this,[cipher,key,options,decipher,iv]);
+ReflectApply(createCipherBase,this,[cipher,key,options,isEncrypt,iv]);
 }
 
 // The Cipher class is part of the legacy Node.js crypto API. It exposes