Alias Iterator

[fabianbs96]

Provides some improvements in handling aliases and pointers:

• Adds AliasIterator, a new, minimal interface for providing alias-information that is more lightweight than AliasInfo
• Adds PointsToIterator, similar to AliasIterator, for points-to information
• Integrate PointsToIterator with SVF points-to info (currently supporting SVF 3.0)
• Integrate LLVM IR-level AliasInfo with alias information from SVF's ContextDDA analysis (currently supporting SVF 3.0)
• Integrate the new AliasIterator and PointsToIterator with the default IFDS/IDE flow-functions
• Splits FilteredLLVMAliasSet into FilteredLLVMAliasIterator and CachedLLVMAliasIterator