Optimize hasAttribute to avoid unnecessary list allocation

[Copilot]

• Replace hasAttribute implementation in src/cil.ml to use List.exists instead of filterAttributes to avoid unnecessary list allocation
• Remove obsolete (* sm: *) comment before hasAttribute

Original prompt

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This section details on the original issue you should resolve

<issue_title>Optimize hasAttribute</issue_title>
<issue_description>It's currently implemented as

cil/src/cil.ml

Lines 1429 to 1430 in bf39f60

	let hasAttribute s al =
	(filterAttributes s al <> [])

This is silly because filterAttributes will allocate a new list, just to check containment. This should be done with List.exists or something reasonable that doesn't allocate at all.

This showed up as a notable source of allocations while analyzing rsync. The hasAttribute is used by bitsOffset calculation (to look for packing attributes) which we heavily use in Goblint during semantic_equal of addresses (and their sets).

In addition to the one-liner change, we should evaluate the impact on rsync/sv-benchmarks.

Besides fixing this, it might make sense to also cache the bitsOffset calls on Goblint side.
</issue_description>

Comments on the Issue (you are @copilot in this section)

@michael-schwarz It's really remarkable which places turn out to be hot when properly benchmarking. I think analyze that is worth it just for these insights already.

• Fixes Optimize hasAttribute #221

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