Wrong results with {removeAdditional: 'failing', allErrors: false} and additionalProperties as failing schema

**What version of Ajv are you using? Does the issue happen if you use the latest version?**
I test it with latest AJV V6.6.1. Yes, it is.

**Ajv options object**

```
{
"removeAdditional": "failing",
"allErrors": false
}
```

**JSON Schema**

```
{
"$schema": "http://json-schema.org/draft-07/schema#",
"type": "object",
"properties": {
"requiredProperty": {
"type": "boolean"
}
},
"required": [
"requiredProperty"
],
"additionalProperties": {
"not": {}
}
}
```

**Sample data**

```
{
"foo": 0
}
```

**Your code**

```
var Ajv = require('ajv');
var ajv = new Ajv(options);
var validate = ajv.compile(schema);
var valid = validate(data); //true - but must be false
console.log(validate.errors); // validate.errors !== null
console.log(data); // {} - foo is removed
```

**Errors**
```
[
{
keyword: 'not',
dataPath: '[\'foo\']',
schemaPath: '#/additionalProperties/not',
params: {},
message: 'should NOT be valid'
}
]
```

**What results did you expect?**
I expect:
1. `valid === false` (-)
2. `foo` removed (+)
3. `validate.errors` not null and does not contain error about additionalProperty `foo`, because `foo` is removed from data. (-)

**Are you going to resolve the issue?**
I test it with latest AJV V6.6.1.
I write test and check all other combinations of `removeAdditional` and `allErrors` options and `additionalProperties` schema value. Here is a code (with AJV v4.11.5) http://plnkr.co/edit/ZIPWAn5HB2Ele4YgGVil?p=info
It seems like a bug, or I don't understand behavior.