Gas for the cache and for Script_typed_ir_size

Context

MR !3419 (merged) (and some before that) adds a cache and functions that estimate the size of various values to estimate the size of the cache. This MR adds benchmarks, models and cost functions for the cache accesses and for these new functions. It also instruments the call sites of the cache updates and of the size functions with gas consumption.

This MR does NOT contain definite gas costs! Benchmarks need to be performed after 3419 is finalized and this MR is merged.

This MR also performs some minor drive-by tidying of some sampling-related files in the benchmark infra.

Manually testing the MR

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, the Development Version section of CHANGES.md for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR