Add SPV_KHR_vulkan_memory_model to aggressive_dead_code_elim (#4320)

diff --git a/source/opt/aggressive_dead_code_elim_pass.cpp b/source/opt/aggressive_dead_code_elim_pass.cpp
index 81b2232..9d7256b 100644
--- a/source/opt/aggressive_dead_code_elim_pass.cpp
+++ b/source/opt/aggressive_dead_code_elim_pass.cpp
@@ -996,6 +996,7 @@
       "SPV_EXT_physical_storage_buffer",
       "SPV_KHR_terminate_invocation",
       "SPV_KHR_shader_clock",
+      "SPV_KHR_vulkan_memory_model",
   });
 }