Add new GPU Optimization Guide block register load/store examples

[pengtu]

Adding a New Sample(s)

GPU Optimization Guide registers/block-load-store.cpp and non-block-load-store.cpp

Description

Two examples illustrate the differences in using vector register for block load/store vs gather/scatter, in sync with the GPU Optimization Guide Q3 2022 release.

Checklist

Administrative

• [X] Review sample design with the appropriate Domain Expert: Zhiqiang Ma
• [ ] If you have any new dependencies/binaries, inform the oneAPI Code Samples Project Manager

Code Development

• [X] Implement coding guidelines and ensure code quality. see wiki for details
• [X ] Adhere to readme template
• [X] Enforce format via clang-format config file
• [X ] Adhere to sample.json specification. https://github.com/oneapi-src/oneAPI-samples/wiki/sample-json-specification
• [X] Ensure/create CI test configurations for sample (ciTests field) https://github.com/oneapi-src/oneAPI-samples/wiki/sample-json-ci-test-object
• [X] Run jsonlint on sample.json to verify json syntax. www.jsonlint.com

Security and Legal

• [X] OSPDT Approval (see Project Manager for assistance)
• [X]Compile using the following compiler flags and fix any warnings, the falgs are: "/Wall -Wformat-security -Werror=format-security"
• [ ] Bandit Scans (Python only)
• [X] Virus scan

Review

• [X] Review DPC++ code with Paul Peterseon. (GitHub User: pmpeter1)
• [X] Review readme with Tom Lenth(@tomlenth) and/or Project Manager - not touching README
• [X] Tested using Dev Cloud when applicable