`abortEarly: false` not honored with custom error message

#### Support plan

Community

* *is this issue currently blocking your project?*: yes
* *is this issue affecting a production system?*: yes

#### Context

* *14.15.4*:
* *17.4*:
* *14*:
* *node* (e.g. node, browser, native):
* *standalone* (e.g. hapi application, another framework, standalone, ...):

#### What are you trying to achieve or the steps to reproduce?

I'm trying to upgrade from Joi 14 to 17 and can't reproduce the same behaviour.

In 14 I had something like
```js
export const errorA = "exists and min 2";
export const errorB = "exists and min 5";

export const schema = Joi.object({
a: Joi.string()
.required()
.min(2)
.error(() => ({
message: errorA,
})),
b: Joi.string()
.required()
.min(5)
.error(() => ({
message: errorB,
})),
});
const result = Joi.validate({}, schema, { abortEarly: false, allowUnknown: true });

// result.error.details. would be an array with errorA/B messages
```

I'm trying to do the same with 17 only getting only the first error message ?

```js
const schema = Joi.object({
a: Joi.string()
.required()
.min(2)
.error(() => new Error("exists and min 2")),
b: Joi.string()
.required()
.min(5)
.error(() => new Error("exists and min 5")),
});
const result = schema.validate({}, { abortEarly: false });

// result.error is a single Error("exists and min 2")) instance, not an array
```

I've seen the suggestions to use `messages` but I don't see how to return a single one, something like `code: "any.all"`
This will return an array of `details` with the expected (custom) error message;
```js
const schema = Joi.object({
a: Joi.string()
.required()
.min(2)
.messages({ "any.required": "required, min 2" }),
b: Joi.string()
.required()
.min(5)
.messages({ "any.required": "exists and min 5" }),
});
const result = schema.validate({}, { abortEarly: false });
console.debug(result.error.details);

```
```bash
[
{
message: 'required, min 2',
path: [ 'a' ],
type: 'any.required',
context: { label: 'a', key: 'a' }
},
{
message: 'exists and min 5',
path: [ 'b' ],
type: 'any.required',
context: { label: 'b', key: 'b' }
}
]
```

But if I validate a partially complete input I have to supply the custom message for every validator code in the chain
```js
const schema = Joi.object({
a: Joi.string()
.required()
.min(2)
.messages({ "any.required": "required, min 2" }),
b: Joi.string().required().min(5).messages({
"any.required": "exists and min 5",
"string.min": "exists and min 5",
}),
});
const result = schema.validate({ b: "s" }, { abortEarly: false });

```