test(load): migrate tests from ava to jest

[armano2]

Migrate load tests from ava to jest

Description

proxyquire is dropped as in incompatible with jest, and instead i used builtin jest mocks,
for unknown reason this package was included in lint, but was used only in load,

serial test got merged with other tests (i can change that if its preferred)

How Has This Been Tested?

Unrelated

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 change)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[byCedric]

Looks good, maybe toMatchObject would be a better replacement for deepEquals?

[marionebl]

This is great, thanks! I incorporated the relevant changes here into #786!