Tests: add CMake option to run Cycles regression tests on GPU devices

CYCLES_TEST_DEVICES is a list of devices (CPU, CUDA, OPTIX, OPENCL). It is set
to CPU only by default.

Test output is now writen to build/tests/cycles/<device>, and the HTML report
has separate report pages for the different devices, with option to compare
between CPU and GPU renders.

Various GPU tests are still failing due to CPU/GPU differences, these are to be
fixed or blacklisted still.

Ref T82193

tests/python/modules/global_report.py

@@ -39,6 +39,7 @@ def _write_html(output_dir):
     <div class="container">
         <br/>
         <h1>{title}</h1>
+        <nav aria-label="breadcrumb"><ol class="breadcrumb"><li class="breadcrumb-item active" aria-current="page">Test Reports</li></ol></nav>
         {combined_reports}
         <br/>
     </div>