Support checking for parameter / receiver locality in anonymous functions

[paganma]

• Introduce the symbolic value LocalityContract for representing the locality required by a first-order function.
• Introduce the symbolic value LocalityRequirement representing the locality required for a function argument.
• Introduce TypeLocalityRequirementResolver to replace DeclarationLocalityResolver.resolveRequired*.
• Introduce ExpressionLocalityRequirementResolver for resolving the locality requirement of the left-hand side of an assignment.
• Introduce an ImmediateLocalityContractResolver to resolve the locality contract directly from a function object.
• Introduce a LocalityContractAnalyzer to resolve the locality contracts in a CFG.
• Introduce checkers for the conformance of locality contracts.