Add SYCL-CTS (x86_64/linux) to planned testing

[alan-forbes-cp]

Overview

Add SYCL-CTS (x86_64/linux) to planned testing.

Reason for change

Required for future releases.

Description of change

Sitting along side OPENCL-CTS tests, SYCL-CTS are built, run and artefacts archived.

Anything else we should know?

• x86_64 linux only
• all tests run by default
• scripts and related support files added to .github/scripts
• git patches added to .github/patches
• the option to download a dpcpp release (rather than build) is added (with support for 'previous workflow' download being future work)
• artefact handling includes the use of tar files to avoid the known "execute perms" Github issue
• swap is expanded in the runner (and ninja -j arg reduced) to facilitate SYCL-CTS builds
• note that the following 5 tests fail:

Failed tests:
  cl12/test_event/event::wait does not report asynchronous errors
  cl12/test_group_functions/Group broadcast - *
  cl12/test_group_functions/Sub-group broadcast and select - *
  cl12/test_math_builtin_api/math_builtin_float_base_*
  cl12/test_math_builtin_api/math_builtin_float_double_*