Fix depth buffer sync

[Ralith]

These account for one of the errors reported in #390. I don't see the others on my laptop, but I may try another machine.

[patowen]

On my machine, on this branch, I get the following sync validation errors:
Validation Error: [ SYNC-HAZARD-READ-AFTER-WRITE ] Object 0: handle = 0x2a7f70000000053, name = surface extraction params, type = VK_OBJECT_TYPE_BUFFER; | MessageID = 0xe4d96472 | vkCmdDispatch(): Hazard READ_AFTER_WRITE for VkBuffer 0x2a7f70000000053[surface extraction params] in VkCommandBuffer 0x22f28a14900[post-frame], VkPipeline 0x72303f0000000052[extract], and VkDescriptorSet 0x854315000000025c[], type: VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, binding #0 index 0. Access info (usage: SYNC_COMPUTE_SHADER_UNIFORM_READ, prior_usage: SYNC_CLEAR_TRANSFER_WRITE, write_barriers: SYNC_COMPUTE_SHADER_SHADER_BINDING_TABLE_READ|SYNC_COMPUTE_SHADER_SHADER_SAMPLED_READ|SYNC_COMPUTE_SHADER_SHADER_STORAGE_READ, command: vkCmdUpdateBuffer, seq_no: 1, reset_no: 1). id=SYNC-HAZARD-READ-AFTER-WRITE number=-455515022 queue_labels= cmd_labels= objects=BUFFER 2a7f70000000053 SYNC-HAZARD-READ-AFTER-WRITE

ERROR Validation Error: [ SYNC-HAZARD-WRITE-AFTER-WRITE ] Object 0: handle = 0x59ffe0000000003d, name = indirect, type = VK_OBJECT_TYPE_BUFFER; | MessageID = 0x5c0ec5d6 | vkCmdDispatch(): Hazard WRITE_AFTER_WRITE for VkBuffer 0x59ffe0000000003d[indirect] in VkCommandBuffer 0x22f28a14900[post-frame], VkPipeline 0x72303f0000000052[extract], and VkDescriptorSet 0x363e11000000025b[], type: VK_DESCRIPTOR_TYPE_STORAGE_BUFFER, binding #2 index 0. Access info (usage: SYNC_COMPUTE_SHADER_SHADER_STORAGE_WRITE, prior_usage: SYNC_CLEAR_TRANSFER_WRITE, write_barriers: SYNC_COMPUTE_SHADER_SHADER_BINDING_TABLE_READ|SYNC_COMPUTE_SHADER_SHADER_SAMPLED_READ|SYNC_COMPUTE_SHADER_SHADER_STORAGE_READ, command: vkCmdUpdateBuffer, seq_no: 5, reset_no: 1). id=SYNC-HAZARD-WRITE-AFTER-WRITE number=1544472022 queue_labels= cmd_labels= objects=BUFFER 59ffe0000000003d SYNC-HAZARD-WRITE-AFTER-WRITE

ERROR Validation Error: [ SYNC-HAZARD-WRITE-AFTER-READ ] Object 0: handle = 0x22f24099f50, type = VK_OBJECT_TYPE_QUEUE; | MessageID = 0x376bc9df | vkQueueSubmit(): Hazard WRITE_AFTER_READ for entry 0, VkCommandBuffer 0x22f28a18900[post-frame], Submitted access info (submitted_usage: SYNC_CLEAR_TRANSFER_WRITE, command: vkCmdUpdateBuffer, seq_no: 1, reset_no: 1). Access info (prior_usage: SYNC_COMPUTE_SHADER_UNIFORM_READ, read_barriers: VK_PIPELINE_STAGE_2_DRAW_INDIRECT_BIT|VK_PIPELINE_STAGE_2_VERTEX_SHADER_BIT|VK_PIPELINE_STAGE_2_TESSELLATION_CONTROL_SHADER_BIT|VK_PIPELINE_STAGE_2_TESSELLATION_EVALUATION_SHADER_BIT|VK_PIPELINE_STAGE_2_GEOMETRY_SHADER_BIT|VK_PIPELINE_STAGE_2_FRAGMENT_SHADER_BIT|VK_PIPELINE_STAGE_2_EARLY_FRAGMENT_TESTS_BIT|VK_PIPELINE_STAGE_2_LATE_FRAGMENT_TESTS_BIT|VK_PIPELINE_STAGE_2_COLOR_ATTACHMENT_OUTPUT_BIT|VK_PIPELINE_STAGE_2_COMPUTE_SHADER_BIT|VK_PIPELINE_STAGE_2_BOTTOM_OF_PIPE_BIT|VK_PIPELINE_STAGE_2_TASK_SHADER_BIT_EXT|VK_PIPELINE_STAGE_2_MESH_SHADER_BIT_EXT|VK_PIPELINE_STAGE_2_RAY_TRACING_SHADER_BIT_KHR|VK_PIPELINE_STAGE_2_FRAGMENT_SHADING_RATE_ATTACHMENT_BIT_KHR|VK_PIPELINE_STAGE_2_TRANSFORM_FEEDBACK_BIT_EXT|VK_PIPELINE_STAGE_2_INDEX_INPUT_BIT|VK_PIPELINE_STAGE_2_VERTEX_ATTRIBUTE_INPUT_BIT, queue: VkQueue 0x22f24099f50[], submit: 1, batch: 1, batch_tag: 18, command: vkCmdDispatch, command_buffer: VkCommandBuffer 0x22f28a14900[post-frame], seq_no: 67, reset_no: 1). id=SYNC-HAZARD-WRITE-AFTER-READ number=929810911 queue_labels= cmd_labels= objects=QUEUE 22f24099f50

I believe those are all the unique errors I get. This seems fewer than before, so it works as a partial fix on my end as well.

Thanks for looking into this!