torint: delete a compile-time check that uses SIZEOF_UNSIGNED_INT

[teor2345]

We do not define SIZEOF_UNSIGNED_INT, so this comparison is always false.
Compilers that support -Wundef issue a diagnostic warning for it.

Fixes bug 29958; bugfix on 29537; not in any released version of Tor.

[coveralls]

Pull Request Test Coverage Report for Build 4474

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 3 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.01%) to 62.261%

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Files with Coverage Reduction	New Missed Lines	%
src/core/or/circuitpadding.c	3	92.07%

Totals
Change from base Build 4473:	0.01%
Covered Lines:	46182
Relevant Lines:	74175

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💛 - Coveralls