toplev: --no-multiplex -Ixxx is unreliable

[andikleen]

The test case in tl-tester sometimes fails. I think the problem is that if the system load changes the reruns output different intervals. Right now tl-tester fails somewhat randomly because of this.

The code tries to handle some cases of this, but sometimes it still seems to miss measured values. Need to harden the code more.

• [ ] Later runs have more intervals than first run

Not handled:

• [ ] Later runs have less intervals than first run

• [ ] Some runs have different number of events (how can this happen)