[clang] [analyzer][NFC] Modernize loops in LiveVariables analysis (PR #157670)

[Gábor Horváth via cfe-commits]

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@@ -90,8 +90,8 @@ namespace {
     if (A.isEmpty())
       return B;
 
-    for (typename SET::iterator it = B.begin(), ei = B.end(); it != ei; ++it) {
-      A = A.add(*it);
+    for (const auto &element : B) {
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Xazax-hun wrote:

We have pointers in these sets. Maybe iterating by value would be better to avoid double indirection?

https://github.com/llvm/llvm-project/pull/157670