Whitelist SPV_EXT_demote_to_helper_invocation for opt passes (#3236)

diff --git a/source/opt/aggressive_dead_code_elim_pass.cpp b/source/opt/aggressive_dead_code_elim_pass.cpp
index 761ff7c..2cdf5ff 100644
--- a/source/opt/aggressive_dead_code_elim_pass.cpp
+++ b/source/opt/aggressive_dead_code_elim_pass.cpp
@@ -923,6 +923,7 @@
       "SPV_GOOGLE_hlsl_functionality1",
       "SPV_GOOGLE_user_type",
       "SPV_NV_shader_subgroup_partitioned",
+      "SPV_EXT_demote_to_helper_invocation",
       "SPV_EXT_descriptor_indexing",
       "SPV_NV_fragment_shader_barycentric",
       "SPV_NV_compute_shader_derivatives",
diff --git a/source/opt/local_access_chain_convert_pass.cpp b/source/opt/local_access_chain_convert_pass.cpp
index e5cdc24..a8cf94b 100644
--- a/source/opt/local_access_chain_convert_pass.cpp
+++ b/source/opt/local_access_chain_convert_pass.cpp
@@ -371,6 +371,7 @@
       "SPV_GOOGLE_hlsl_functionality1",
       "SPV_GOOGLE_user_type",
       "SPV_NV_shader_subgroup_partitioned",
+      "SPV_EXT_demote_to_helper_invocation",
       "SPV_EXT_descriptor_indexing",
       "SPV_NV_fragment_shader_barycentric",
       "SPV_NV_compute_shader_derivatives",
diff --git a/source/opt/local_single_block_elim_pass.cpp b/source/opt/local_single_block_elim_pass.cpp
index a465483..c66271e 100644
--- a/source/opt/local_single_block_elim_pass.cpp
+++ b/source/opt/local_single_block_elim_pass.cpp
@@ -248,6 +248,7 @@
       "SPV_GOOGLE_hlsl_functionality1",
       "SPV_GOOGLE_user_type",
       "SPV_NV_shader_subgroup_partitioned",
+      "SPV_EXT_demote_to_helper_invocation",
       "SPV_EXT_descriptor_indexing",
       "SPV_NV_fragment_shader_barycentric",
       "SPV_NV_compute_shader_derivatives",