Partially revert 48302989 to fix pxf_regress

[ostinru]

In this PR:

• revert changes from 4830298 to fix regression: pxf_regress will agian rise an error when diff is found
• mark broken tests with enabled = false and TODO comment

Fixes #86

[MisterRaindrop]

There is no tracking issue to ensure these tests will be fixed later, making them easy to forget. Should we record them in an issue to avoid forgetting?

[ostinru]

There is no tracking issue to ensure these tests will be fixed later, making them easy to forget. Should we record them in an issue to avoid forgetting?

Left it here as checklist: #86 (comment)