Fix: max-statements-per-line false positive (fixes #6173, fixes #6153)

[mysticatea]

Fixes #6173,
Fixes #6153.

I rewrote the traversal logic of this rule.
Before, it uses a for loop in BlockStatement handler.
After this PR, it uses ESLint's traversing. So this rule gets addressing nested nodes correctly.

[eslintbot]

LGTM

[mention-bot]

By analyzing the blame information on this pull request, we identified @vitorbal, @glenjamin and @alberto to be potential reviewers

[glenjamin]

I'm not sure about the name "dangling host type", but this looks much more solid than the old way.

I was surprised how little traversal there was in here when I came to do the last patch!

[glenjamin]

Maybe "single child allowed" - naming based on the usage rather than the category

[eslintbot]

LGTM

[mysticatea]

Thank you, @glenjamin. I updated the variable name.

I try to explain more since this PR is a large change.
This rule is depending on traversal order. It's checking whether a statement exists in the same line as the previous statement. But it was using wrong order.

---

a; if (b) { c; d; }
y;
z;

In this case, before, the order is a → if (b) → y → z → c → d. Then, y is not the same line as if (b). c is not the same line as z. It had wrong order for nested statements. So the rule will show unintentional result on this code.

After this PR, the order is a → if (b) → c → d → y → z. This addresses nested nodes correctly.

---

if (a)
    b;
else
    c;

In this case, the order is if (a) → c in both before and after.
Before, it was comparing between the first line of a statement and the last line of the previous statement, for all cases. So the rule will show unintentional result on this code because the last line of IfStatement and the first line of c; is the same (this is #6173).

After this PR, it will use the first line of statements for nested statements. So in this case, it will compare between the first lines of the IfStatement and c;.

[nzakas]

Lgtm