Compiler fuzzer to ensure Tact correctness

[anton-trunov]

The approach described in the Random testing of a higher-order blockchain language paper proved to be efficient for ensuring the correctness of an implementation of a smart contract language.

This should be ideally integrated to CI, although it might require some self-hosted infrastructure to run randomized tests for long periods of time (hours in some cases).

This requires the following steps:

• Choose a property-based testing framework with suitable performance (at least 10k AST nodes per second)
• Fuzz a minimal Tact subset: pure functions, a single contract with getters
  • Generate well-typed AST expressions
  • Write properties to test that generators generate well-typed expressions
  • Generate pure functions based on the given signature
  • Generate well-formed contracts with getters and some fields
  • Write a property that checks whether the generated contract translates to valid FunC code addressing Tact produces FunC code with errors #118
  • Implement infrastructure to execute the generated contract
• Support the stateful subset of Tact