Update: curly should check consequent if statements

[mdjermanovic]

Prerequisites checklist

• I have read the contributing guidelines.
• The team has reached consensus on the changes proposed in this pull request. If not, I understand that the evaluation process will begin with this pull request and won't be merged until the team has reached consensus.

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

[X] Bug fix

This bug fix produces more warnings.

Tell us about your environment

• ESLint Version: v7.0.0-alpha.1
• Node Version: v12.14.0
• npm Version: v6.13.4

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

default

Please show your full configuration:

Configuration

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

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

Demo Link (v.6.8.0)

/* eslint curly: ["error", "multi"] */

if (a)
    if (b) {
        foo();
    }

if (a)
    if (b)
        foo();
    else {
        bar();
    } 

if (a)
    if (b)
        foo();
    else if (c) {
        bar();
    }

What did you expect to happen?

3 errors.

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

No errors.

The whole chain is ignored if it happens to be in another if's consequent.

What changes did you make? (Give an overview)

Fixed the IfStatement visitor to skip only those if statements that are alternate of another if (because they were already processed as a chain), but not if statements that are consequent of another if.

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

[kaicataldo]

LGTM, thanks!