CONTRACTS: optimize is_fresh separation checks, add ptr predicate uniqueness checks

[remi-delmas-3000]

• Replaces a bool array indexed by object ID by a nondet demonic variable to
  track the set of fresh objects and implement separation checks.
• Ensures requires or ensures clause assume/assert at most one predicate
  per pointer by tracking locations where these pointers are stored and adding
  separation checks on them as well. This is necessary to catch and reject occurences like
  __CPROVER_is_fresh(p, size) && __CPROVER_is_fresh(p, size) that would pass in assume
  contexts by allocating twice but fail in assert contexts.
• Adds a new type __CPROVER_contracts_ptr_pred_ctx_t in cprover_contracts.c
  to store all contextual information needed to evaluate all pointer predicates.
• Propagate changes to dfcc_libraryt and dfcc_wrapper_programt.
• Add new tests for pointer assumption uniqueness checks.
• Fix failing tests that used is_fresh under negation in ensures.
• Update dev doc

• Each commit message has a non-empty body, explaining why the change was made.
• Methods or procedures I have added are documented, following the guidelines provided in CODING_STANDARD.md.
• The feature or user visible behaviour I have added or modified has been documented in the User Guide in doc/cprover-manual/
• Regression or unit tests are included, or existing tests cover the modified code (in this case I have detailed which ones those are in the commit message).
• My commit message includes data points confirming performance improvements (if claimed).
• My PR is restricted to a single feature or bugfix.
• White-space or formatting changes outside the feature-related changed lines are in commits of their own.

[codecov]

Codecov Report

Attention: Patch coverage is 82.05128% with 7 lines in your changes missing coverage. Please review.

Project coverage is 78.85%. Comparing base (3d79560) to head (d7d0aec).

Files with missing lines	Patch %	Lines
.../contracts/dynamic-frames/dfcc_wrapper_program.cpp	70.00%	6 Missing ⚠️
...strument/contracts/dynamic-frames/dfcc_library.cpp	93.75%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #8573      +/-   ##
===========================================
- Coverage    78.92%   78.85%   -0.07%     
===========================================
  Files         1732     1732              
  Lines       198953   199119     +166     
  Branches     18560    18560              
===========================================
+ Hits        157021   157023       +2     
- Misses       41932    42096     +164     

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[remi-delmas-3000]

@tautschnig I see some perf regressions on the AWS-commons library but the patch includes additional checks anyways. I'll iterate once more on this.

[hanno-becker]

mlkem-native test here: pq-code-package/mlkem-native#688

[remi-delmas-3000]

Closing, will split the PR in two separate PRs