util: test_timeline.ts - allow multiple syncs at the same time

[xiashtra]

Currently, the test_timeline.ts utility will complain about missed syncs that occur at the exact same time but in a different order. It would be nice if the utility could handle multiple syncs at the same time, regardless of order they occur in the timeline or log.

Ref: #5474 (comment)

[quisquous]

One example of this from test_timeline.ts on the variant dungeon:

      +0.020 |  638 | 5175.6 "Arcane Intervention 1" sync / 1[56]:[^:]*:Quaqua:8BAE:/
      -0.018 |  639 | 5184.6 "Arcane Intervention 2" sync / 1[56]:[^:]*:Quaqua:8BAE:/
      -0.063 |  640 | 5193.6 "Arcane Intervention 3" sync / 1[56]:[^:]*:Quaqua:8BAE:/
      Missed |  641 | 5196.6 "Arcane Intervention 4" sync / 1[56]:[^:]*:Quaqua:8BAE:/
      -0.032 |  643 | 5196.6 "--middle--" sync / 1[56]:[^:]*:Quaqua:8B8F:/
       0.000 |  641 | 5196.6 "Arcane Intervention 4" sync / 1[56]:[^:]*:Quaqua:8BAE:/
      Missed |  643 | 5196.6 "--middle--" sync / 1[56]:[^:]*:Quaqua:8B8F:/
      +0.033 |  644 | 5202.8 "Arcane Armaments" sync / 1[56]:[^:]*:Quaqua:8B90:/

You can see that there are two abilities at 5196.6 and they come in the opposite order and look like errors.