WHPX: TSC get and set should be dependent on VM state

Currently, TSC is set as part of the VM runtime state. Setting TSC at
runtime is heavy and additionally can have side effects on the guest,
which are not very resilient to variances in the TSC. This patch uses
the VM state to determine whether to set TSC or not. Some minor
enhancements for getting TSC values as well that considers the VM state.

Additionally, while setting the TSC, the partition is suspended to
reduce the variance in the TSC value across vCPUs.

Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Message-Id: <SN4PR2101MB08804D23439166E81FF151F7C0EA0@SN4PR2101MB0880.namprd21.prod.outlook.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>