subgroups: Add missing algorithm header (#1906)
* Was causing a build error with GN
* fill_and_shuffle_safe_values() in subhelpers.cpp calls std::shuffle()
* std::shuffle is defined in <algorithm>
diff --git a/test_conformance/subgroups/subhelpers.cpp b/test_conformance/subgroups/subhelpers.cpp
index 440cde2..0899ef9 100644
--- a/test_conformance/subgroups/subhelpers.cpp
+++ b/test_conformance/subgroups/subhelpers.cpp
@@ -16,6 +16,7 @@
#include "subhelpers.h"
+#include <algorithm>
#include <random>
// Define operator<< for cl_ types, accessing the .s member.
