Added unittests for reference ECC implementation.

[ Merge of http://go/wvgerrit/114284 ]

The unittests check that the ECC keys are being created as expected
and that they can perform their basic operations.

Bug: 135283522
Test: oemcrypto_unittests
Change-Id: I1bdb26421ba47e1ab135f5ce5a54da304627a7c3

libwvdrmengine/oemcrypto/ref/src/oemcrypto_ecc_key.cpp

@@ -4,6 +4,8 @@
 //
 //  Reference implementation of OEMCrypto APIs
 //
+#include "oemcrypto_ecc_key.h"
+
 #include <assert.h>
 #include <string.h>
 
@@ -18,7 +20,6 @@
 #include <openssl/x509.h>
 
 #include "log.h"
-#include "oemcrypto_ecc_key.h"
 #include "scoped_object.h"
 
 namespace wvoec_ref {