What is the purpose of this pull request? (put an "X" next to item)

[X] Bug fix #12169

Tell us about your environment

• ESLint Version: 6.4.0
• Node Version: 10.16.0
• npm Version: 6.9.0

What parser (default, Babel-ESLint, etc.) are you using?

Please show your full configuration:

module.exports = {
  parserOptions: {
    ecmaVersion: 2015,
  }
};

What did you do? Please include the actual source code causing the issue.

/* eslint no-misleading-character-class: ["error"] */

var r = new RegExp('[Á] [ ');

What did you expect to happen?

Not to crash.

What actually happened? Please include the actual, raw output from ESLint.

SyntaxError: Invalid regular expression: /[Á] [ /: Unterminated character class
    at RegExpValidator.raise ...

What changes did you make? (Give an overview)

try/catch to ignore invalid regular expressions.

Is there anything you'd like reviewers to focus on?

The original issue is about regex literals with @typescript-eslint/parser, but the same applies to the regex constructor with the default parser.

I think it isn't necessary to add a @typescript-eslint/parser test since it's testable with the default?