[BUG] jinja sls variables like sls, slspath, tpldir are not loaded for saltcheck.run_state_tests

Description
SLS Jinja variables described here
https://docs.saltproject.io/en/latest/ref/states/vars.html
are not available in the context for saltcheck.run_state_tests

At least the following ones do not seem to be resolved properly for saltcheck states
{{ tpldir }}
{{ slspath }}
{{ sls }}

Setup
Trying to use these variables to import a jinja map file that provides settings to be used in the saltcheck state.

{%- set tplroot = tpldir.split('/')[0] %}
{% from tplroot ~ "/map.jinja" import settings with context %}

The jinja template is not found due the variables return none.

A hardcoded string works fine

{% from"path_to_state/map.jinja" import settings with context %}

Steps to Reproduce the behavior
Create a jinja map file and a saltcheck state to use it, try importing the jinja map file using tpldir or slspath variables

Expected behavior
These variables should be loaded in a similar way than it's done for state.sls

Start with saltcheck.run_state_tests and compare its Jinja context with the state.sls behavior described in the linked SLS variables documentation. Reproduce the issue using a map.jinja import based on tpldir or slspath; done means those variables resolve and the import succeeds in a saltcheck state.