Properly reject octal number literals

[Y-Nak]

What was wrong?

Currently, the analyzer doesn't consider number literals that start with 0. This leads to ICE in the yul mapping pass.
fixes #222

How was it fixed?

Reject a number literal if it starts with 0 and has more than two digits.

To-Do

• OPTIONAL: Update Spec if applicable
• Add entry to the release notes (may forgo for trivial changes)
• Clean up commit history

Related problem

I also found that lexer doesn't tokenize correctly if number literals start with 0 followed by non zero value.
For example, 02 is tokenized into

    [
        Token {
            typ: NUMBER,
            string: "0",
            span: Span {
                start: 0,
                end: 1,
            },
            line: "02\n",
        },
        Token {
            typ: NUMBER,
            string: "2",
            span: Span {
                start: 1,
                end: 2,
            },
            line: "02\n",
        },
        Token {
            typ: NEWLINE,
            string: "\n",
            span: Span {
                start: 2,
                end: 3,
            },
            line: "02\n",
        },
        Token {
            typ: ENDMARKER,
            string: "",
            span: Span {
                start: 3,
                end: 3,
            },
            line: "",
        },
    ],

I'll open an issue for this and address it in another PR.

EDIT: opened #331.

[g-r-a-n-t]

This is great! Thanks for the contribution 🦀