radv: implement VK_EXT_vertex_input_dynamic_state

This implements VK_EXT_vertex_input_dynamic_state using vertex shader prologs.

Since there are not many tests for this extension, https://gitlab.freedesktop.org/pendingchaos/mesa/-/commits/radv_ext_vertex_input_dynamic_state_testing can be used to test prologs with static vertex input state.

A couple future improvements are to improve scheduling in the main shader and to reduce CPU overhead.