Record POWER provider by default in lab traces

The POWER provider is needed because CPU frequency can have a huge
effect on power usage - if the CPU frequency goes higher then CPU
usage may be lower while power usage is higher. The POWER provider
records CPU frequency and CPU power-state changes.

LabScripts/GeneralTracing/set_vars.bat

@@ -40,8 +40,9 @@ rem PROC_THREAD+LOADER are required in order to know what binaries are loaded
 rem and what threads are running.
 rem CSWITCH records context switch data so that precise CPU usage and context
 rem switch counts can be recorded. So, these three flags are our minimum set
-rem of kernel providers.
-set KernelProviders=PROC_THREAD+LOADER+CSWITCH
+rem of kernel providers. I then add in +POWER so that we can see CPU frequency
+rem and power-state changes.
+set KernelProviders=PROC_THREAD+LOADER+CSWITCH+POWER
 
 rem These user providers record GPU usage, window-in-focus, eventemitter events
 rem (if emitted), and process working-set samples.

LabScripts/GeneralTracing/start_tracing.bat

@@ -39,7 +39,7 @@ rem which we optionally enable for lab tracing.
 rem This extra information will distort timings. This is particularly true
 rem of the CSwitch and ReadyThread stackwalk flags.
 set KernelProviders=%KernelProviders%+CSWITCH+DISK_IO+HARD_FAULTS+DPC+INTERRUPT+PROFILE
-set KernelProviders=%KernelProviders%+POWER+DISPATCHER+DISK_IO_INIT+FILE_IO+FILE_IO_INIT+VIRT_ALLOC+MEMINFO
+set KernelProviders=%KernelProviders%+DISPATCHER+DISK_IO_INIT+FILE_IO+FILE_IO_INIT+VIRT_ALLOC+MEMINFO
 set StackWalkFlags=Profile+CSwitch+ReadyThread
 xperf.exe -start %logger% -on %KernelProviders% -stackwalk %StackWalkFlags% -buffersize 1024 -minbuffers 160 -maxbuffers 160 -f "%kernelfile%" -start %SessionName% -on %UserProviders% -f "%userfile%
 :skipdetailed