gpuav: check for VK_EXT_pipeline_robustness disabling robustness

DescriptorClassGeneralBufferPass skips some of its checks if the device-level robustBufferAccess feature is enabled. It should not skip those checks when VK_EXT_pipeline_robustness is used to disable robustness for a specific pipeline.

Simple test is to turn on robustnessBufferAccess, then create a pipeline with (and without) robustness turned off, then make sure GPU-AV is catching that one

Start at DescriptorClassGeneralBufferPass and reproduce the described GPU-AV scenario with robustBufferAccess enabled, creating pipelines with and without robustness disabled through VK_EXT_pipeline_robustness. Done means GPU-AV catches the issue when pipeline-level robustness is disabled while preserving the expected behavior when it is not.

Written by the indexing model from the issue text.