[GR-64675] Introduce TypeFlow.flowState

[graalvmbot]

This PR merges three TypeFlow volatile integer fields isEnabled,isSaturated, and predicateTriggered into a single flowState field. It saves 8B per flow instance and we allocate millions of flows when building bigger images, so we can expect reduction in terms of tens of MB. Not a groundbreaking improvement, but relatively simple to implement. Apart from footprint reduction, this change also helps to more explicitly capture the possible state transitions each flow may go through.

This PR also includes a refactoring that caches PointstoOptions.TrackAccessChain and PointstoOptions.ParsingContextMaxDepth in AnalysisPolicy, which are currently queried inside every AnalysisMethod constructor (and AnalysisField constructor for TrackAccessChain).