Increase number of runs for all performance benchmarks

[sequba]

After increasing the number of runs for basic performance benchmarks (currently 100 runs, #1303), I see much less noise in their results (see screenshot). The benchmarks will be much more useful to us if they were run less often but with greater accuracy (I'd make all benchmarks run 100 times).

Example performance report: first 4 benchmarks run 100 times, last 5 run only once:

[sequba]

Released with version 2.6.2.