vcsim: Support PlaceVm with relocate placement type

[yanleizhao-vmware]

Description

This patch introduces basic support for ClusterComputeResource.PlaceVm with the relocate placement type in vcsim. Since relocate is a supported placement type in real vSphere environments, it is essential to ensure that our simulator environment reflects this capability for accurate and comprehensive testing.

Closes: #3540

Type of change

Please mark options that are relevant:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to
  not work as expected)
• This change requires a documentation update
• Build related change

How Has This Been Tested?

All of the added unit tests simulate behavior (i.e., expected Faults/Recommendations) when testing the same PlacementSpec against a real vSphere environment.

% go test -v -count 1 -run 'TestPlaceVm' -coverprofile cover.out ./simulator

=== RUN   TestPlaceVmReconfigure
2024/09/06 14:56:08 unsupported placement type: unsupported
--- PASS: TestPlaceVmReconfigure (1.76s)
=== RUN   TestPlaceVmRelocate
--- PASS: TestPlaceVmRelocate (0.39s)
=== RUN   TestPlaceVmsXCluster
--- PASS: TestPlaceVmsXCluster (0.87s)
PASS
coverage: 27.4% of statements
ok      github.com/vmware/govmomi/simulator     3.455s  coverage: 27.4% of statements

go tool cover -html=cover.out -o=coverage.html 

100% code coverage on new code:

Checklist:

• My code follows the CONTRIBUTION guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged

[dougm]

Thanks @yanleizhao-vmware , lgtm. Just a couple minor suggestions

[dougm]

Thanks @yanleizhao-vmware ,
Can you please squash the review fixup commits first?

[yanleizhao-vmware]

Thanks @yanleizhao-vmware , Can you please squash the review fixup commits first?

Of course, I wasn't sure if using squash and fixup is recommended, or tolerated 😅

[dougm]

Thanks @yanleizhao-vmware !