Flame Chart not populated properly for LTTng UST traces with call stack data

[bhufmann]

The Flame Chart is currently not populated properly. Most of the function states are not shown. Only a view are visible as well as some "GAP" states.

[bhufmann]

After some debugging, it turns out that the there was an exception generated when trying to calculate an array index using a key and modulo operation for the coloring. The uncaught exception is caused because the key (parentKey below) is negative:

style = backupStyles[(hash(stateStyle.parentKey) as number % backupStyles.length)];

This uncaught exception actually, causes any updates to retrieve data from the server to not be executed because a flag is not reset. This is actually in the timeline-chart implementation. A fix needs to be done to always reset the flag.
https://github.com/theia-ide/timeline-chart/blob/006aac473e90a00c4abbf1a7088a5d788ac1c6de/timeline-chart/src/layer/time-graph-chart.ts#L222

[bhufmann]

Note that the data provider for the flame graph should also provide the styles for the coloring, but that is not in the scope of this issue.