Include FP16 header for conversions

PiperOrigin-RevId: 314854321
diff --git a/test/vbinaryc-microkernel-tester.h b/test/vbinaryc-microkernel-tester.h
index 4dc0bbd..6297259 100644
--- a/test/vbinaryc-microkernel-tester.h
+++ b/test/vbinaryc-microkernel-tester.h
@@ -15,6 +15,8 @@
 #include <random>
 #include <vector>
 
+#include <fp16.h>
+
 #include <xnnpack.h>
 #include <xnnpack/params-init.h>
 #include <xnnpack/params.h>