don't sign test assembly (#6289)

build/config/AssemblySignToolData.json

@@ -55,6 +55,7 @@
   ],
   "exclude": [
     "e_sqlite3.dll",
+    "FSharp.Core.UnitTests.dll",
     "FSharp.Data.TypeProviders.dll",
     "Microsoft.Build.dll",
     "Microsoft.Build.Framework.dll",

build/config/PackageSignToolData.json

@@ -18,6 +18,7 @@
         "FSharp.Compiler.Interactive.Settings.dll",
         "FSharp.Compiler.Private.dll",
         "FSharp.Core.dll",
+        "FSharp.Core.UnitTests.dll",
         "fsi.exe"
     ]
 }
\ No newline at end of file