Do not use check inheritance

[hithwen]

Having inheritance on a check will cause the agent to not load it properly. The issue presents in this case when there is more than one instance of the check. The first instance will load the child class and the second instance will fail to find the parent class

The fix here (we can think of something more elegant for long term) is to pass the parent class to the now not children classes and explicitly call it instead of using self

[codecov]

Codecov Report

Merging #9433 (2453234) into master (e9d9395) will increase coverage by 0.01%.
The diff coverage is 96.00%.

Flag	Coverage Δ
tls	97.04% <96.00%> (+0.87%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
tls/datadog_checks/tls/tls_remote.py	81.19% <92.30%> (+1.02%)	⬆️
tls/datadog_checks/tls/tls.py	96.21% <100.00%> (-0.06%)	⬇️
tls/datadog_checks/tls/tls_local.py	100.00% <100.00%> (ø)
tls/tests/test_local.py	100.00% <100.00%> (ø)
tls/tests/test_remote.py	100.00% <100.00%> (+1.38%)	⬆️
tls/datadog_checks/tls/utils.py	100.00% <0.00%> (+9.30%)	⬆️