[Feature] TensorShape string layout descriptors

[zacharyvincze]

Motivation

Adds additional constructors to TensorShape to define tensor layouts through string descriptors rather than enums.

Test Plan

• Changes the TensorShape construction method in test_tensor.cpp to ensure it still compiles/passes tests.

Test Result

• C++ tests passing as expected.

Submission Checklist

• Look over the contributing guidelines at https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.

[Copilot]

Pull Request Overview

This PR adds new string-based constructor overloads to the TensorShape class, allowing developers to specify tensor layouts using string descriptors (e.g., "NHWC", "HWC") instead of enum values. This provides a more convenient and readable way to create tensor shapes.

Key changes:

• Added string-to-enum mapping functionality for tensor layout descriptors
• Added two new TensorShape constructors that accept string layout descriptors
• Updated test cases to use the new string-based constructors

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
include/core/tensor_shape.hpp	Added new constructor declarations with string layout descriptors and updated documentation
src/core/tensor_shape.cpp	Implemented string-to-enum mapping function and new string-based constructors
tests/roccv/cpp/test_tensor.cpp	Updated all test cases to use new string-based TensorShape constructor syntax

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