core/marco: fix DIV_ROUND

[kfessel]

#18856 lead to huge implementations this does that better a more efficient DIV_ROUND_UINT is not required

Contribution description

this fixes DIV_ROUND
this fixes DIV_ROUND_UP and documents its now reliable behavior
this add DIV_ROUND_INF which round away from 0 (the original intended behavior of DIV_ROUND_UP)

this adds Tests that test the DIV_ROUND* macros with negative inputs

Testing procedure

read, test, run tests/unitest/ core

<RIOT>/tests/unittests$ make tests-core term

Issues/PRs references

have a test at
https://godbolt.org/z/bEvT6Wzr9

#18849
#18856
#18853

[riot-ci]

Murdock results

✔️ PASSED

aa31dd7 core/macros: rewrite DIV_ROUND, DIV_ROUND_UP; add DIV_ROUND_INF

Success	Failures	Total	Runtime
2002	0	2002	06m:23s

Artifacts

• Documentation preview

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[kfessel]

alternative:

#define DIV_ROUND_UP(a, b) ((SIGNOF(a) == SIGNOF(b)) ? (((a) + (b) - SIGNOF(a)) / (b)): (a) / (b))

this one seems to produce less good code (needs more stack if put into its own function)