Primitive malloc freshness analysis

[sim642]

This is a very primitive malloc freshness analysis that should be sufficient for the initializations in zstd and chrony.

Changes

1. Add mallocFresh analysis, which keeps a must-set of fresh alloc variables, which are used for excluding races. The set is very easily forgotten to hopefully ensure soundness.
2. Add zstd custom allocation functions to LibraryFunctions. This is necessary because due to some invalidation somewhere, unknown pointer gets added to possible values, despite the program only ever using custom allocators with NULL. These are only used when added to exp.extraspecials.
3. (Add conf for analyzing zstd races such that all spurious races are now gone!) To be readded to interactive.
4. Handle address set result in base branch.
5. Handle address set in base logical not expression.

TODO

• Figure out why doesn't work on full zstd. Due to custom allocator? Yes.
• Check if works on chrony. @vesalvojdani
• Rebase to master.
• Readd zstd-race conf when merging to interactive.

[vesalvojdani]

Yes, it eliminates all races for Chrony.

[sim642]

Using the included conf, all the spurious zstd races are gone!

[Warning][Race] Memory location ((alloc@sid:15485), lib/common/pool.c:122:5-122:68)[?].threadLimit@lib/common/pool.c:122:5-122:68 (race with conf. 110):
  read with [symblock:{p-lock:*.queueMutex}, mhp:{tid=POOL_thread; created=All Threads}] (conf. 110) (lib/common/pool.c:74:9-84:9)
  write with [mhp:{tid=main; created=All Threads}, thread:main] (conf. 110) (lib/common/pool.c:158:9-158:38)

Summary for all memory locations:
        safe:         2390
        vulnerable:      0
        unsafe:          1
        -------------------
        total:        2391

EDIT: Actually the remaining race is also spurious, but for rather subtle reasons: the read happens while ctx->queueEmpty == 1 and the write happens while ctx->queueEmpty == 0. So some kind of symbolic privatization and access partitioning by those symbolically privatized values might be able to rule it out, but that's too far-fetched for the time being.