fix: test case ut_lind_fs_mmap_invalid_offset_len

[ChinmayShringi]

Description

Fixes # (issue)

This PR updates the test case ut_lind_fs_mmap_invalid_offset_len by get_errno(), ensuring compliance with the error-checking mechanisms and proper retrieval of errno. The test case verifies the behavior of the mmap_syscall when invalid offsets (negative and beyond EOF) are provided, ensuring that EINVAL is returned appropriately. These changes improve the test case's accuracy and reliability without modifying the existing syscall implementation.

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• cargo test ut_lind_fs_mmap_invalid_offset_len

Checklist:

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• Any dependent changes have been added to a pull request and/or merged in other modules (native-client, lind-glibc, lind-project)