venus: support VK_KHR_push_descriptor

• extend lifetime of push descriptor set layout
• extend VkPipelineLayout lifetime for batched VkCmdPushConstants()
• enable extension VK_KHR_push_descriptor

venus_protocol:https://gitlab.freedesktop.org/olv/venus-protocol/-/merge_requests/51

virglrenderer:virgl/virglrenderer!946 (merged)

test cases:

- dEQP-VK.api.object_management.*
  Passed:        417/421 (99.0%)
  Failed:        0/421 (0.0%)
  Not supported: 0/421 (0.0%)
  Warnings:      4/421 (1.0%)
- dEQP-VK.binding_model.shader_access.primary_cmd_buf.with_push_template.*
  Passed:        3198/3198 (100.0%)
- dEQP-VK.binding_model.shader_access.primary_cmd_buf.with_push.*
  Passed:        3198/3198 (100.0%)
- dEQP-VK.binding_model.shader_access.primary_cmd_buf.with_template.* 
  Passed:        8276/8276 (100.0%)

Signed-off-by: Dawn Han dawnhan@google.com

/cc @zzyiwei @chadversary @ryanneph