Add test for multipleOf to ensure that implementation does not have an issue regarding scale

This is not a float/double related issue but is one regarding scale. Consider the following schema:

[
    {
        "description": "by deep scale",
        "schema": {"multipleOf": 0.25},
        "tests": [
            {
                "description": "8.75 is multiple of 0.25",
                "data": 8.75,
                "valid": true
            },
            {
                "description": "8.750000000001 is not multiple of 0.25",
                "data": 8.750000000001,
                "valid": false
            },
            {
                "description": "8.7500000000001 is not multiple of 0.25",
                "data": 8.7500000000001,
                "valid": false
            },
            {
                "description": "8.75000000000001 is not multiple of 0.25",
                "data": 8.75000000000001,
                "valid": false
            }
        ]
    }
]

This will ensure libraries with language support for a rich big decimal are not constrained by a low exponent check.

Locate the test fixture containing multipleOf cases and review how numeric validation examples are organized. Add the provided deep-scale schema cases, then run the JSON Schema Test Suite checks to confirm 8.75 is valid while each more precise value is invalid.