Harden examiner test execution with canonical path validation and strict input handling-Pr 838 base Branch

[Srustisundar]

1. Added strict validation for test names to ensure only simple filenames are accepted.
2. Validated command aguments once and reused the sanitized result to avoid accidental reintroduction of untrusted input.
   3.Resolved executable paths to their canonical (real) filesystem paths before execution.
3. Verified that the canonical path still resides within the allowed examiner directories, preventing symlink-based escapes.
4. Added a defense-in-depth validation before process execution to make intent clear and auditable.

Why this was done
Static analysis flagged the previous implementation due to potential ambiguity around child process execution paths.
Although practical exploitation was already constrained, this hardening removes any remaining doubt by making all trust boundaries explicit also increases the veracode security score

[jorgemoralespou]

hey @Srustisundar All looks fine except for the reformatting of existing code and change in formatting style. But we can fix that in a later PR, since we need to add global formatter

[jorgemoralespou]

@GrahamDumpleton Are you ok with this PR?