Give some convenient idiomatic accessors to Stmt::child_range and
Stmt::const_child_range, then make a bunch of places use them instead
of the individual iterator accessors.

llvm-svn: 125450
diff --git a/clang/lib/AST/StmtProfile.cpp b/clang/lib/AST/StmtProfile.cpp
index 707cac4..b96ffe8 100644
--- a/clang/lib/AST/StmtProfile.cpp
+++ b/clang/lib/AST/StmtProfile.cpp
@@ -68,8 +68,7 @@
 
 void StmtProfiler::VisitStmt(Stmt *S) {
   ID.AddInteger(S->getStmtClass());
-  for (Stmt::child_iterator C = S->child_begin(), CEnd = S->child_end();
-       C != CEnd; ++C)
+  for (Stmt::child_range C = S->children(); C; ++C)
     Visit(*C);
 }