PR #3955 removes mono_dl_open() and mono_loader_register_module() from
msvc/mono.def and msvc/monosgen.def which causes VS linking error. This change
readds the symbols to the def files as a temporary solution to get the VS
builds to build successfully again.
mono_disasm_code_one
mono_dl_fallback_register
mono_dl_fallback_unregister
+mono_dl_open
mono_dllmap_insert
mono_domain_add_class_static_data
mono_domain_assembly_open
mono_ldtoken
mono_load_remote_field
mono_load_remote_field_new
+mono_loader_register_module
mono_lock_free_alloc
mono_lock_free_allocator_check_consistency
mono_lock_free_allocator_init_allocator
mono_disasm_code_one
mono_dl_fallback_register
mono_dl_fallback_unregister
+mono_dl_open
mono_dllmap_insert
mono_domain_add_class_static_data
mono_domain_assembly_open
mono_ldtoken
mono_load_remote_field
mono_load_remote_field_new
+mono_loader_register_module
mono_lock_free_alloc
mono_lock_free_allocator_check_consistency
mono_lock_free_allocator_init_allocator