Fix Testing Framework in the JSOO build

Motivation and Context

ligo.js doesn't have a working testing framework.

Description

This MR uses a patched version of protocol to let us use it for the testing framework.

Protocol is written with 64-bit environment in mind. Browsers, however, are 32-bit (as far as JSOO is concerned). This MR adapts saturation_repr.ml to use Zarith's Z.t so that when compiled to JS, zarith's stubs get linked in and get us 64 bit emulation for integer arithmetic in the browser.

Note: one of the interpreter step invocation passes zero gas as the initial state. I don't know where this is coming from as of now. To workaround this, the gas costs of all instructions are temporarily made free.

Component

• compiler
• website
• webide
• vscode-plugin
• debugger

Types of changes

• 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)
• Performance improvement (non-breaking change that improves performance)
• None (change with no changelog)

Changelog

Fixes testing framework in ligo.js

Checklist:

• Changes follow the existing coding style (use dune @fmt to check).
• Tests for the changes have been added (for bug fixes / feature).
• Documentation has been updated.
• Changelog description has been added (if appropriate).
• Start titles under ## Changelog section with #### (if appropriate).
• There is no image or uploaded file in changelog
• Examples in changed behaviour have been added to the changelog (for breaking change / feature).