[clang] [NFC][analyzer] Refactor Environment to map Expr to SVal instead of Stmt to SVal (PR #193295)

[Balázs Benics via cfe-commits]

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@@ -377,10 +377,10 @@ class ProgramState : public llvm::FoldingSetNode {
   /// Get the lvalue for an array index.
   SVal getLValue(QualType ElementType, SVal Idx, SVal Base) const;
 
-  /// Returns the SVal bound to the statement 'S' in the state's environment.
-  SVal getSVal(const Stmt *S, const LocationContext *LCtx) const;
+  /// Returns the SVal bound to the expression 'E' in the state's environment.
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steakhal wrote:

```suggestion
  /// Returns the SVal bound to the expression \p E in the state's environment.
```

https://github.com/llvm/llvm-project/pull/193295