Fix SAI_STATUS_IS_* attribute-range helpers for negative status codes

[MoriLevinzon]

Fixes #2307

Two fixes in the SAI_STATUS_IS_* helpers in inc/saistatus.h:

• Compare on the magnitude (SAI_STATUS_CODE(x)) before masking, so the range
  check is correct for negative status codes on Linux. Previously a non-zero
  attribute index borrowed across the 16-bit boundary and matched the wrong
  range (e.g. INVALID_ATTR_VALUE index 3 classified as ATTR_NOT_IMPLEMENTED).
  No-op on Windows, where SAI_STATUS_CODE is identity.
• Fix SAI_STATUS_IS_UNKNOWN_ATTRIBUTE, which compared against
  SAI_STATUS_INVALID_ATTRIBUTE_0 instead of SAI_STATUS_UNKNOWN_ATTRIBUTE_0
  (wrong on all platforms).

[kcudnik]

Related: #1570 #1235

[kcudnik]

if you are changing this, add unittests in sanitycheck for corner cases like suggested here: #1235

[MoriLevinzon]

Added check_status_attr_ranges() in meta/saisanitycheck.c (called from main), covering the corner cases from #1235 for all five attribute-error ranges:

Encoding value: SAI_STATUS_0 + SAI_STATUS_CODE(index) == SAI_STATUS_CODE(base + index).
Classification: each indexed code matches its own SAI_STATUS_IS* helper and no other (this also covers the SAI_STATUS_IS_UNKNOWN_ATTRIBUTE wrong-base fix).
Boundaries: indices 0, 1, _MAX and _MAX-1 (the MAX-2 case from), plus the codes just below _0 and just above _MAX must not match.
Index round-trip: the decoded attribute index equals the input.
Sentinels must not match: SAI_STATUS_SUCCESS, SAI_STATUS_FAILURE, SAI_STATUS_NOT_EXECUTED, 1, -1.

The test passes with the fixed macros and fails against the current ones, so it guards the fix. Verified it compiles under the meta flags (-Wconversion -Werror).

[kcudnik]

/azp run

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[kcudnik]

update aspell:

WARNING: Word 'xFFFF' is misspelled ./saisanitycheck.c

[MoriLevinzon]

update aspell:

WARNING: Word 'xFFFF' is misspelled ./saisanitycheck.c

Added xFFFF to meta/aspell.en.pws

[kcudnik]

/azp run

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[kcudnik]

we could update aspell to automatically exclude all hexadecimal numbers instead of adding each one somewhere here https://github.com/opencomputeproject/SAI/blob/master/meta/aspellcheck.pl#L190

[MoriLevinzon]

we could update aspell to automatically exclude all hexadecimal numbers instead of adding each one somewhere here https://github.com/opencomputeproject/SAI/blob/master/meta/aspellcheck.pl#L190

Updated meta/aspellcheck.pl to skip C-style hexadecimal literals and removed the one-off xFFFF entry from meta/aspell.en.pws, so future hex constants won't need dictionary additions

[kcudnik]

thanks

[kcudnik]

/azp run

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Azure Pipelines successfully started running 1 pipeline(s).

[MoriLevinzon]

Thanks @kcudnik! All checks are green and it's approved — please merge when you can