Add dependency on System.Security.Permissions

Author: wtgodbe

tests/src/Common/test_dependencies/project.json

@@ -3,7 +3,8 @@
     "Microsoft.NETCore.Platforms": "2.0.0-preview1-25214-03",
     "Microsoft.Private.CoreFx.NETCoreApp": "4.4.0-preview1-25214-03",
     "System.Memory": "4.4.0-preview1-25214-03",
-    "System.Runtime.CompilerServices.Unsafe": "4.4.0-preview1-25214-03"
+    "System.Runtime.CompilerServices.Unsafe": "4.4.0-preview1-25214-03",
+    "System.Security.Permissions": "4.4.0-preview1-25214-03"
   },
   "frameworks": {
     "netcoreapp2.0": {