Code review comment for lp://staging/~mir-team/mir/more-performance-tests

The mir glmark2 performance tests are taking too long by default (5min * N, N is currently 6).

Suggestions:

1. Reduce the amount of time spent in each benchmark scene. This can be achieved with a "-b :duration=2" option (apply duration of 2 seconds to all benchmark scenes)

2. Cherrypick only a few benchmark scenes to run by default. This is again controlled with "-b" command line arguments.

3. Both of the above