Test compare function with/without callback

[bkowshik]

There are a couple of compare functions with the old style callback format. Ex:

• invalid_tag_combination.js

A majority of compare function have moved over to the new, plain return format. Ex:

• added_place.js

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@batpad @lukasmartinelli Any ideas how to make tests/test_compare_function.js work for both these use cases? In this PR, I have modified the test to work for the plain return format as that looks like the majority of the compare functions.

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cc: @amishas157 @geohacker

[amishas157]

@bkowshik

Any ideas how to make tests/test_compare_function.js work for both these use cases? In this PR, I have modified the test to work for the plain return format as that looks like the majority of the compare functions.

To make it work for all the compare functions, I added the commit to import compare functions from index file itself, which exports all compare functions as async functions.

Should that be fine?

cc @batpad

[amishas157]

To clarify, the above commit does a bunch of things apart from solving above issue. This is the part of the commit which is specific to the above issue