[test] Print out profiling statistics after a successful test run

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/tests/test.c

 #include <ipxe/test.h>
 #include <ipxe/init.h>
 #include <ipxe/image.h>
+#include <usr/profstat.h>
 
 /** Current self-test set */
 static struct self_test *current_tests;
 		return -EINPROGRESS;
 	} else {
 		printf ( "OK: all %d tests passed\n", total );
+		profstat();
 		return 0;
 	}
 }