[runtime] Use coop handles for the remaining System.Reflection.Assembly icalls (#4082)
* [reflection] Use handles for System.Reflection.Assembly.GetFilesInternal
* [reflection] Use handles for System.Reflection.Assembly.InternalGetType
* [reflection] Use handles for System.Reflection.Assembly.GetManifestResourceNames
* [reflection] Use handles for System.Reflection.Assembly.LoadPermissions
* [reflection] Add mono_method_get_object_handle
Reimplement mono_method_get_object_checked in terms of the handles one.
* [reflection] Use handles for System.Reflection.Assembly.get_EntryPoint
* [reflection] Use handles for four more icalls in System.Refleciton.Assembly
That's the lot of them.
* get_ReflecitonOnly
* get_code_base
* get_fullname
* get_global_assembly_cache
* [security] Use handles for System.Security.Policy.Evidence.IsAuthenticodePresent
* [runtime] Use handles for System.Web.Util.Icalls.GetUnmanagedResourcesPtr
* [runtime] Use MONO_HANDLE_GETVAL instead of MONO_HANDLE_RAW in a few places
* [runtime] Use handles for System.AppDomain.ExecuteAssembly