Compute 2020 12 updated (#17975)

* adding 2020-12-01 compute generated files

* update default sku

* update tests

* test updates

* records

* tests fixes

* all the recorded tests

* more update

* more update

* more update

* last test fixes

* Updated TestVMIdentitySystemAssignedUserAssigned SDK Test to create User Assigned Identity using SDK (#17861)

* Updated TestVMIdentitySystemAssignedUserAssigned SDK Test to create User Assigned MI using MSI SDK

* Resolved Merge Conflicts and updated the test

Co-authored-by: Pavan Rachapudy <vrachapu@microsoft.com>

* Delete AppGW tests (#17977)

* Delete VMScaleSetAppGwWithAS.json

* Delete VMScaleSetAppGwWithAS_A1V2.json

* Delete VMScaleSetAppGwWithAS_SPG_False.json

* Delete VMScaleSetAppGwWithAS_Spot.json

* Delete VMScaleSetAppGWTests.cs

* Delete deprecated ContainerService tests (#17976)

* Delete ContainerServiceOperationalTests.cs

* Delete ContainerServiceTestsBase.cs

* Delete ContainerServiceUpdateTests.cs

* Delete TestDCOSOperations.json

* Delete TestSwarmOperations.json

* Delete TestContainerServiceUpdateOperations.json

* test

* remove test text

Co-authored-by: pavanrachapudy <pavanrachapudy@gmail.com>
Co-authored-by: Pavan Rachapudy <vrachapu@microsoft.com>
Co-authored-by: Adam Sandor <adsandor@microsoft.com>