opt: add SPV_EXT_mesh_shader to opt allowlist (KhronosGroup#5551)

Add this extension to the allowlist, allowing DCE and other
optimizations on modules exposing this.
Note: NV equivalent is already allowed.

Author: Keenuts

source/opt/aggressive_dead_code_elim_pass.cpp

@@ -985,6 +985,7 @@ void AggressiveDCEPass::InitExtensions() {
       "SPV_NV_shader_image_footprint",
       "SPV_NV_shading_rate",
       "SPV_NV_mesh_shader",
+      "SPV_EXT_mesh_shader",
       "SPV_NV_ray_tracing",
       "SPV_KHR_ray_tracing",
       "SPV_KHR_ray_query",

source/opt/local_access_chain_convert_pass.cpp

@@ -420,8 +420,8 @@ void LocalAccessChainConvertPass::InitExtensions() {
        "SPV_EXT_demote_to_helper_invocation", "SPV_EXT_descriptor_indexing",
        "SPV_NV_fragment_shader_barycentric",
        "SPV_NV_compute_shader_derivatives", "SPV_NV_shader_image_footprint",
-       "SPV_NV_shading_rate", "SPV_NV_mesh_shader", "SPV_NV_ray_tracing",
-       "SPV_KHR_ray_tracing", "SPV_KHR_ray_query",
+       "SPV_NV_shading_rate", "SPV_NV_mesh_shader", "SPV_EXT_mesh_shader",
+       "SPV_NV_ray_tracing", "SPV_KHR_ray_tracing", "SPV_KHR_ray_query",
        "SPV_EXT_fragment_invocation_density", "SPV_KHR_terminate_invocation",
        "SPV_KHR_subgroup_uniform_control_flow", "SPV_KHR_integer_dot_product",
        "SPV_EXT_shader_image_int64", "SPV_KHR_non_semantic_info",

source/opt/local_single_block_elim_pass.cpp

@@ -273,6 +273,7 @@ void LocalSingleBlockLoadStoreElimPass::InitExtensions() {
                                 "SPV_NV_shader_image_footprint",
                                 "SPV_NV_shading_rate",
                                 "SPV_NV_mesh_shader",
+                                "SPV_EXT_mesh_shader",
                                 "SPV_NV_ray_tracing",
                                 "SPV_KHR_ray_tracing",
                                 "SPV_KHR_ray_query",

source/opt/local_single_store_elim_pass.cpp

@@ -124,6 +124,7 @@ void LocalSingleStoreElimPass::InitExtensionAllowList() {
                                 "SPV_NV_shader_image_footprint",
                                 "SPV_NV_shading_rate",
                                 "SPV_NV_mesh_shader",
+                                "SPV_EXT_mesh_shader",
                                 "SPV_NV_ray_tracing",
                                 "SPV_KHR_ray_query",
                                 "SPV_EXT_fragment_invocation_density",