fix: handle exceptions during superuser switch

[soedirgo]

Ensure switch_to_original_role() gets called if an exception happens after switch_to_superuser() - otherwise is_switched_to_superuser is left in an inconsistent state.

[coveralls]

Pull Request Test Coverage Report for Build 19501006832

Details

• 27 of 32 (84.38%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.4%) to 88.502%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/supautils.c	27	32	84.38%

Totals
Change from base Build 19299320771:	0.4%
Covered Lines:	1016
Relevant Lines:	1148

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💛 - Coveralls

[steve-chavez]

I understand the logic, but I worry about the repetition of run_process_utility_hook_with_cleanup and if it's needed in every place. This retry might affect us in unexpected ways.

I have a WIP for #79, which should reduce the calls to run_process_utility_hook, gimme a couple of days to see if finishing that leads to a better solution.