fix(#978): speed up bytes-without-data lint

[ext11n7]

What this PR does

Optimizes the bytes-without-data lint by replacing expensive XPath predicates with a cheaper structural check.

Instead of evaluating eo:has-data() and eo:abstract() for every matching node, the lint now selects only nodes that:

• are children of Φ.bytes
• have no @base
• have no non-empty text content

Why

The previous XPath was too slow on large XMIR files.

On the benchmark source set, bytes-without-data improved on XXL from 138ms to 69ms, which brings it below the 100ms threshold from the issue.

Validation

• benchmark suite passed
• XSL test suite passed

[ext11n7]

@yegor256

[yegor256]

@volodya-lombrozo check it please

[0crat]

@ext11n7 It is not a good idea to name Git branches the way you named this one: "bytes-without-data". You've earned -6 points. Next time, better give your branch the same name as the number of the ticket that you are solving. In this case, a perfect name, for example, would be "1015". Your running score is +4; don't forget to check your Zerocracy account too).