refactored pre-check

[ammokhov]

Issue #, if available: https://github.com/aws-cloudformation/aws-cloudformation-resource-providers-logs/issues/39

Description of changes:

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[miparnisari]

I ran integration tests with this PR:

I also ran them with this PR+removing the Read after the Create & Update operations:

[ammokhov]

I ran integration tests with this PR:

I also ran them with this PR+removing the Read after the Create & Update operations:

latest change results of 7 integ tests:

SUCCESSFUL in 2m 49s

[miparnisari]

============================================== short test summary info ==============================================
FAILED handler_update.py::contract_update_create_only_property - UnboundLocalError: local variable 'created_model'...
FAILED handler_update.py::contract_update_non_existent_resource - AssertionError: status should be FAILED
ERROR handler_delete.py::contract_delete_read - AssertionError: assert 'resourceModel' not in {'callbackDelaySecon...
ERROR handler_delete.py::contract_delete_list - AssertionError: assert 'resourceModel' not in {'callbackDelaySecon...
ERROR handler_delete.py::contract_delete_update - AssertionError: assert 'resourceModel' not in {'callbackDelaySec...
ERROR handler_delete.py::contract_delete_delete - AssertionError: assert 'resourceModel' not in {'callbackDelaySec...
ERROR handler_delete.py::contract_delete_create - AssertionError: assert 'resourceModel' not in {'callbackDelaySec...
===================== 2 failed, 7 passed, 1 skipped, 9 warnings, 5 errors in 152.70s (0:02:32) ======================
One or more contract tests failed

We need to fix this before publishing the type