Processing logic for frame statistics can be moved out of fps instrument
to a new utility file. This will allow result processors to use the same
logic to produce frame statistics on a subsection of the data
produced by the fps instrument.
Added -p option to the list command. This alows filtering results by
supported platforms, e.g.
wa list workloads -p linux
Also adding missing supported_platforms attribute to various extensions.
If an extension does not have this attribute, the assumption is that it
is supported by all available platforms.
