Improvements for cancelable operations

[spoenemann]

• Use performance.now() for time measurements (see Performance.now vs. Date.now)
• Use the startCancelableOperation function to reset the lastTick variable: in the current state, interruptAndCheck leads to unnecessary delays at the beginning of an operation because the internal variable used to compare the elapsed time is outdated. This change eliminates those unnecessary delays on document changes.

[msujew]

Shouldn't we use performance.now() here as well?

langium/packages/langium/src/utils/promise-utils.ts

Line 34 in 5be87ad

lastTick = Date.now();

[msujew]

LGTM 👍