Switch users of the 'for (StmtRange range = stmt->children(); range; ++range)‘ pattern to range for loops.

The pattern was born out of the lack of range-based for loops in C++98
and is somewhat obscure. No functionality change intended.

llvm-svn: 241300
diff --git a/clang/lib/Analysis/AnalysisDeclContext.cpp b/clang/lib/Analysis/AnalysisDeclContext.cpp
index 4e623c8..d7fb7e9 100644
--- a/clang/lib/Analysis/AnalysisDeclContext.cpp
+++ b/clang/lib/Analysis/AnalysisDeclContext.cpp
@@ -472,9 +472,9 @@
   : BEVals(bevals), BC(bc) {}
 
   void VisitStmt(Stmt *S) {
-    for (Stmt::child_range I = S->children(); I; ++I)
-      if (Stmt *child = *I)
-        Visit(child);
+    for (Stmt *Child : S->children())
+      if (Child)
+        Visit(Child);
   }
 
   void VisitDeclRefExpr(DeclRefExpr *DR) {