CSE Machine: Avoid pushing unnecessary env instructions (exhaustive version)

[DiligentPenguinn]

Description

This PR aims to implement an exhaustive version of PR #1699 and #1687 .
A ControlItem is environment-dependent if its evaluation depends on the current environment, OR its evaluation introduces environment-dependent items onto the control.
At each step, if the current control is free of environment-dependent items then we can avoid pushing environment instruction.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Code quality improvements

Some of my concerns

1. How exhaustive should the logic be? I think it’s enough to cover all node types and instructions allowed to be used in Source. Any remaining node types can default to being environment-independent

2. I initially wanted to place the logic in the AST file along with statementSeqTransform but I realized the logic needed to work for control items which can be either nodes or instructions. Instructions are only defined within the CSE Machine context so currently I place the logic there.

3. I modified the test cases to use generateCSEMachineStateStream which allows me to check the number of environment-dependent items at each step, but now the test runs synchronously (because generateCSEMachineStateStream runs synchronously). Would this be a problem?

[coveralls]

Pull Request Test Coverage Report for Build 10793927514

Details

• 76 of 76 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.06%) to 81.61%

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Totals
Change from base Build 10793919938:	0.06%
Covered Lines:	10983
Relevant Lines:	13081

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💛 - Coveralls

[RichDom2185]

Hi, did a quick look and just some questions below

[martin-henz]

Good work. I think this will be a good improvement to reduce the number of env instructions.