IdleWakeups updates

IdleWakeups expects to build with VS 2015 which we don't otherwise use -
this upgrades it to VS 2017.

One of the IdleWakeups columns was "Working Set" but that is ambiguous
so I confirmed that it is Private Working Set and changed the label
appropriately.

Change-Id: I49c0810de8b5ef1fce59764a05bf2b909ec9739a
Reviewed-on: https://chromium-review.googlesource.com/c/1457670
Auto-Submit: Bruce Dawson <brucedawson@chromium.org>
Commit-Queue: Sébastien Marchand <sebmarchand@chromium.org>
Reviewed-by: Sébastien Marchand <sebmarchand@chromium.org>
Cr-Commit-Position: refs/heads/master@{#634768}

tools/win/IdleWakeups/idle_wakeups.cpp

@@ -255,6 +255,7 @@ void PrintHeader() {
       "------------------------------------------------------------------------"
       "----------\n");
   printf(
+      "                                                            Private\n"
       "                       Context switches/sec    CPU usage    Working set "
       "     Power\n");
   printf(