clutter: add tracing for frameclock cycle
This adds a new frameclock tracing mark for a single cycle of the frame clock. Doing so allows Sysprof to potentially do more with the information that happens during the frameclock. For example, we can now find allocations that happen while the frameclock is advancing.
For example, in Sysprof you can now print information about allocations per frame:
...
4.118374-4.119083: 6.4 KiB
4.135661-4.136365: 6.4 KiB
4.152056-4.152733: 6.4 KiB
4.288280-4.303005: 265.6 KiB
4.328380-4.358271: 494.5 KiB
4.378165-4.382268: 18.9 KiB
4.394932-4.398745: 42.9 KiB
...
72.828589-72.828808: 1.3 KiB
72.843994-72.844095: 1.3 KiB
72.860288-72.860425: 1.3 KiB
72.877616-72.877702: 1.3 KiB
72.894113-72.894187: 1.3 KiB
Min: 56 bytes, Max: 6.9 MiB, Avg: 34.5 KiB, Median: 26.9 KiB