vcsim: Enhanced sim support for upgrade VM

[akutz]

Description

This patch enhances the simulator's support for the upgradeVm API as well as introduces the helper type vim25/types.HardwareVersion for parsing and comparing VMX hardware versions.

Closes: NA

Type of change

Please mark options that are relevant:

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] 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?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. If applicable, please also list any relevant details for your test configuration.

• [x] Test 1

  $ go test -v -count 1 -run 'TestUpgradeVm' ./simulator
  === RUN   TestUpgradeVm
  === RUN   TestUpgradeVm/InvalidPowerState
  === RUN   TestUpgradeVm/InvalidState
  === RUN   TestUpgradeVm/InvalidState/MaintenanceMode
  === RUN   TestUpgradeVm/InvalidState/Template
  === RUN   TestUpgradeVm/InvalidState/LatestHardwareVersion
  === RUN   TestUpgradeVm/NotSupported
  === RUN   TestUpgradeVm/NotSupported/AtAll
  === RUN   TestUpgradeVm/NotSupported/OnVmHost
  === RUN   TestUpgradeVm/AlreadyUpgraded
  === RUN   TestUpgradeVm/AlreadyUpgraded/EqualToTargetVersion
  === RUN   TestUpgradeVm/AlreadyUpgraded/GreaterThanTargetVersion
  === RUN   TestUpgradeVm/InvalidArgument
  === RUN   TestUpgradeVm/UpgradeFrom15To17
  === RUN   TestUpgradeVm/UpgradeFrom17To20
  === RUN   TestUpgradeVm/UpgradeFrom15To17To20
  --- PASS: TestUpgradeVm (0.22s)
      --- PASS: TestUpgradeVm/InvalidPowerState (0.00s)
      --- PASS: TestUpgradeVm/InvalidState (0.00s)
          --- PASS: TestUpgradeVm/InvalidState/MaintenanceMode (0.00s)
          --- PASS: TestUpgradeVm/InvalidState/Template (0.00s)
          --- PASS: TestUpgradeVm/InvalidState/LatestHardwareVersion (0.00s)
      --- PASS: TestUpgradeVm/NotSupported (0.00s)
          --- PASS: TestUpgradeVm/NotSupported/AtAll (0.00s)
          --- PASS: TestUpgradeVm/NotSupported/OnVmHost (0.00s)
      --- PASS: TestUpgradeVm/AlreadyUpgraded (0.00s)
          --- PASS: TestUpgradeVm/AlreadyUpgraded/EqualToTargetVersion (0.00s)
          --- PASS: TestUpgradeVm/AlreadyUpgraded/GreaterThanTargetVersion (0.00s)
      --- PASS: TestUpgradeVm/InvalidArgument (0.00s)
      --- PASS: TestUpgradeVm/UpgradeFrom15To17 (0.00s)
      --- PASS: TestUpgradeVm/UpgradeFrom17To20 (0.00s)
      --- PASS: TestUpgradeVm/UpgradeFrom15To17To20 (0.00s)
  PASS
  ok      github.com/vmware/govmomi/simulator 0.952s

• [x] Test 2

  $ go test -v -count 1 -run TestHardwareVersion ./vim25/types
  === RUN   TestHardwareVersion
  === RUN   TestHardwareVersion/empty_string
  === RUN   TestHardwareVersion/vmx_prefix_sans_number
  === RUN   TestHardwareVersion/number_sans_vmx_prefix
  === RUN   TestHardwareVersion/vmx-13
  === RUN   TestHardwareVersion/VMX-18
  --- PASS: TestHardwareVersion (0.00s)
      --- PASS: TestHardwareVersion/empty_string (0.00s)
      --- PASS: TestHardwareVersion/vmx_prefix_sans_number (0.00s)
      --- PASS: TestHardwareVersion/number_sans_vmx_prefix (0.00s)
      --- PASS: TestHardwareVersion/vmx-13 (0.00s)
      --- PASS: TestHardwareVersion/VMX-18 (0.00s)
  PASS
  ok      github.com/vmware/govmomi/vim25/types   0.322s

Checklist:

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