CSE Machine fixes for variadic functions, closures & heap

[CZX123]

Description

This PR fixes many issues related to the new heap addition.

Changes

• Created duplicate Closure class for use in the CSE Machine
• Made closureToJS use CSE Machine instead of the old interpreter
  • This will allow the built-in function apply_in_underlying_javascript to correctly display the environment and ensure objects get added to the heap correctly
• Added new declaredName property in Closure, which stores the name of the constant variable the closure is assigned to
  • This is used for apply_in_underlying_javascript to create environment frames with better names
  • functionName will now always be in the form of x => ...
• Correctly added the argument array of a variadic closure to the heap
• Added environment property to functions returned from calling stream
• Added move method in Heap for use in the frontend
• Moved Stack and IStack to a separate file to avoid circular dependency issues

[coveralls]

Pull Request Test Coverage Report for Build 8608170634

Details

• 90 of 95 (94.74%) changed or added relevant lines in 6 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.07%) to 81.932%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/cse-machine/stack.ts	12	13	92.31%
src/cse-machine/closure.ts	46	50	92.0%

Totals
Change from base Build 8608095546:	0.07%
Covered Lines:	10687
Relevant Lines:	12693

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💛 - Coveralls

[martin-henz]

Good work. Quite a few cleanups and improvements.

[martin-henz]

Great to see "closure" in this folder instead of using the legacy interpreter implementation.