unistd: fix _resolve_abspath() errno setting

[adamdebek]

In some cases an invalid errno set in _readlink_abs() propageted outside the function

JIRA: RTOS-981

Description

Motivation and Context

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (refactoring, style fixes, git/CI config, submodule management, no code logic changes)

How Has This Been Tested?

• Already covered by automatic testing.
• New test added: (add PR link here).
• Tested by hand on: (list targets here).

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing linter checks and tests passed.
• My changes generate no new compilation warnings for any of the targets.

Special treatment

• This PR needs additional PRs to work (list the PRs, preferably in merge-order).
• I will merge this PR by myself when appropriate.

[github-actions]

Unit Test Results

7 958 tests  +9   7 416 ✅ +185   40m 16s ⏱️ +3s
  470 suites +9     542 💤  - 176 
    1 files   ±0       0 ❌ ±  0 

Results for commit 1aed303. ± Comparison against base commit 089ebfb.

This pull request removes 729 and adds 738 tests. Note that renamed tests count towards both.

phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.A
phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.E
phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.F
phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.G
phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.a
phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.e
phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.f
phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.g
phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.inf_nan_a
phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.inf_nan_e
…

phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_aefg.A
phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_aefg.E
phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_aefg.F
phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_aefg.G
phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_aefg.a
phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_aefg.e
phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_aefg.f
phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_aefg.g
phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_aefg.inf_nan_a
phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_aefg.inf_nan_e
…

This pull request removes 137 skipped tests and adds 33 skipped tests. Note that renamed tests count towards both.

phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.A
phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.E
phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.F
phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.G
phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.a
phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.e
phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.f
phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.g
phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.inf_nan_a
phoenix-rtos-tests/libc/scanf ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf.stdio_scanf_aefg.inf_nan_e
…

phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_rest.m_brackets
phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_rest.m_c
phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_rest.m_s
phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a7-imx6ull-evk:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_squareBrackets.white_spaces
phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a9-zynq7000-qemu:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_rest.m_brackets
phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a9-zynq7000-qemu:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_rest.m_c
phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a9-zynq7000-qemu:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_rest.m_s
phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a9-zynq7000-qemu:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_squareBrackets.white_spaces
phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a9-zynq7000-zedboard:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_rest.m_brackets
phoenix-rtos-tests/libc/scanf-advanced ‑ armv7a9-zynq7000-zedboard:phoenix-rtos-tests/libc/scanf-advanced.stdio_scanf_rest.m_c
…