[clang][NFC] Clean up Expr::EvaluateAsConstantExpr (#130498)

The Info.EnableNewConstInterp case is already handled above.

Author: tbaederr

clang/lib/AST/ExprConstant.cpp

@@ -16903,24 +16903,19 @@ bool Expr::EvaluateAsConstantExpr(EvalResult &Result, const ASTContext &Ctx,
   APValue::LValueBase Base(&BaseMTE);
   Info.setEvaluatingDecl(Base, Result.Val);
 
-  if (Info.EnableNewConstInterp) {
-    if (!Info.Ctx.getInterpContext().evaluateAsRValue(Info, this, Result.Val))
-      return false;
-  } else {
-    LValue LVal;
-    LVal.set(Base);
-    // C++23 [intro.execution]/p5
-    // A full-expression is [...] a constant-expression
-    // So we need to make sure temporary objects are destroyed after having
-    // evaluating the expression (per C++23 [class.temporary]/p4).
-    FullExpressionRAII Scope(Info);
-    if (!::EvaluateInPlace(Result.Val, Info, LVal, this) ||
-        Result.HasSideEffects || !Scope.destroy())
-      return false;
+  LValue LVal;
+  LVal.set(Base);
+  // C++23 [intro.execution]/p5
+  // A full-expression is [...] a constant-expression
+  // So we need to make sure temporary objects are destroyed after having
+  // evaluating the expression (per C++23 [class.temporary]/p4).
+  FullExpressionRAII Scope(Info);
+  if (!::EvaluateInPlace(Result.Val, Info, LVal, this) ||
+      Result.HasSideEffects || !Scope.destroy())
+    return false;
 
-    if (!Info.discardCleanups())
-      llvm_unreachable("Unhandled cleanup; missing full expression marker?");
-  }
+  if (!Info.discardCleanups())
+    llvm_unreachable("Unhandled cleanup; missing full expression marker?");
 
   if (!CheckConstantExpression(Info, getExprLoc(), getStorageType(Ctx, this),
                                Result.Val, Kind))