Simplify vcsim endpoint setup

[dougm]

What this PR does / why we need it:

The vcsim 'RegisterEndpoints' flag was added after the initial version of vsphere_test was written. With the flag set, tests only need to import the simulator packages it needs.

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

See: vmware/govmomi#3178

Special notes for your reviewer:

@lubronzhan another option when bumping the govmomi version is the patch below. But this PR will also simplify the code a bit.

modified   pkg/cloudprovider/vsphere/vsphere_test.go
@@ -96,7 +96,7 @@ func configFromSimWithTLS(tlsConfig *tls.Config, insecureAllowed bool, multiDc b
 	model.Service.ServeMux.Handle(path, handler)
 
 	// vAPI simulator
-	vapiPath, handler := vapi.New(s.URL, nil)
+	vapiPath, handler := vapi.New(s.URL, simulator.Map)
 	model.Service.ServeMux.Handle(vapiPath[0], handler)
 
 	// Lookup Service simulator

Release note:

NONE

[lubronzhan]

/lgtm
/approve
Thanks Doug!

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dougm, lubronzhan

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [dougm,lubronzhan]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment