Ensure that <iterator> is included before back_inserter is used

Closes #2231

include/internal/benchmark/catch_execution_plan.hpp

@@ -19,6 +19,7 @@
 #include "detail/catch_run_for_at_least.hpp"
 
 #include <algorithm>
+#include <iterator>
 
 namespace Catch {
     namespace Benchmark {

include/internal/catch_interfaces_reporter.h

@@ -21,6 +21,8 @@
 #if defined(CATCH_CONFIG_ENABLE_BENCHMARKING)
 #include "benchmark/catch_estimate.hpp"
 #include "benchmark/catch_outlier_classification.hpp"
+
+#include <iterator>
 #endif // CATCH_CONFIG_ENABLE_BENCHMARKING