Create test pattern for Spans

Part of https://github.com/apache/datafusion-sqlparser-rs/issues/1548

# Usecase

- We have added span information in https://github.com/apache/datafusion-sqlparser-rs/pull/1435

We would like to add span information through out the rest of the AST structures (see docs in https://github.com/apache/datafusion-sqlparser-rs/pull/1549) and list on https://github.com/apache/datafusion-sqlparser-rs/issues/1548

In order to support this feature reasonably, we need to be able to test the feature and avoid regressions

# Proposal

I think we need some sort of span test.

I recommend
1. A new test binary like `tests/sqlparser_spans.rs`

Then add a test that
1. Parses a SQL string
2. Check the spans of the AST nodes match what is expected

I think we'll have to use judgement on how fine grained the location information
can / should be.

Read the context in issues 1548 and 1563, plus PRs 1435 and 1549, to understand the existing span information and planned AST coverage. Start with the proposed tests/sqlparser_spans.rs entry point: parse representative SQL strings and compare AST-node spans with expected locations. Done means the span behavior is covered by tests and regressions can be detected.

Written by the indexing model from the issue text.