turnip: Tessellation shaders

This MR implements tessellation support for turnip. The actual changes are better described by the individual commit messages, but at a high level this MR contains commits to:

• Configure and enable tessellation shader compilation
• Update ir3_nir_lower_tess to support NIR generated from SPIR-V
• Allocate and grow tess BOs
• Emit tess-related configuration
• Support half-regs for HS/DS/GS on a6xx

In addition, this MR depends on some changes I made to the SPIR-V to NIR compiler in !5058 (closed). With this MR, turnip now passes all tess-related tests in the VK CTS (dEQP-VK.tessellation.*) except for a few that fail due to RA alloc crashes:

• dEQP-VK.tessellation.shader_input_output.cross_invocation_per_vertex_mat4x3
• dEQP-VK.tessellation.shader_input_output.cross_invocation_per_vertex_vec3
• dEQP-VK.tessellation.shader_input_output.cross_invocation_per_vertex_vec4

/cc @krh