[clang][dataflow] Add `buildAndSubstituteFlowCondition` to `DataflowEnvironment`

[wyt]

Summary

Depends On D128658

[wyt]

Fix comment.

[wyt]

Propagate change from parent patch.

clang/include/clang/Analysis/FlowSensitive/DataflowEnvironment.h

public:
   /// will be a value that represents the true boolean literal.
   BoolValue &makeIff(BoolValue &LHS, BoolValue &RHS) const {
     return DACtx->getOrCreateIff(LHS, RHS);
   }
 
   /// Returns the token that identifies the flow condition of the environment.
   AtomicBoolValue &getFlowConditionToken() const { return *FlowConditionToken; }
 
+  /// Builds and returns the logical formula defining the flow condition
+  /// identified by `Token`. If a value in the formula is present as a key in
+  /// `Substitutions`, it will be substituted with the value it maps to.
+  BoolValue &buildAndSubstituteFlowCondition(
+      AtomicBoolValue &Token,
+      llvm::DenseMap<AtomicBoolValue *, BoolValue *> Substitutions) {
+    return DACtx->buildAndSubstituteFlowCondition(Token,
+                                                  std::move(Substitutions));
+  }
+
   /// Adds `Val` to the set of clauses that constitute the flow condition.
   void addToFlowCondition(BoolValue &Val);
 
   /// Returns true if and only if the clauses that constitute the flow condition
   /// imply that `Val` is true.
   bool flowConditionImplies(BoolValue &Val) const;
 
 private: