8213148: JDK build fails because of missing #includes

Add missing #includes

Reviewed-by: dcubed

test/hotspot/gtest/memory/test_metaspace.cpp

@@ -24,6 +24,8 @@
 #include "precompiled.hpp"
 #include "memory/metaspace.hpp"
 #include "memory/metaspace/virtualSpaceList.hpp"
+#include "runtime/mutexLocker.hpp"
+#include "runtime/os.hpp"
 #include "unittest.hpp"
 
 using namespace metaspace;