profiling: move default mode to "real" time

Mercurial operations involve a lot of disks or network access. These impact
command runtime significantly and it seems important to report them in our
default profiling output.

Having the right default means that we don't forget them when asking people to
produces profiling traces or when doing profiling ourselves.

Moving to "real time" by default will remove the need to think about
activating it on most occasions. The "CPU" time-based profiling is still
accessible when necessary.

mercurial/configitems.py

@@ -923,7 +923,7 b" coreconfigitem('profiling', 'statformat'"
     default='hotpath',
 )
 coreconfigitem('profiling', 'time-track',
-    default='cpu',
+    default='real',
 )
 coreconfigitem('profiling', 'type',
     default='stat',