Fix: xgenerator reports memory overlap to avoid in-place assignment corruption

[Tyagiquamar]

Fixes #2819. xgenerator's overlapping_memory_checker_traits returned false unconditionally, so assignment from an xgenerator reading its resized target (e.g. xt::concatenate into itself) could read uninitialized memory. Report true so a temporary is used. Root cause analysis in BYTEASK.md.

[codspeed]

Merging this PR will not alter performance

⚠️ 1 benchmark measured no execution time

Nothing ran under measurement, usually because the compiler removed the code under test. This result is not comparable, so it counts as unchanged.

Preventing compiler optimizations

• create_xview

✅ 255 untouched benchmarks

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_{Comparing Tyagiquamar:fix-xgenerator-overlap-2819 (e8acbeb) with master (d9a57b6)}