Fix potential integer overflows identified by Coverity

Convert ODK_LAST_STRESSABLE_TYPE to an aliased enum value so that
ODK_FieldLength always returns a valid value instead of SIZE_MAX.

PiperOrigin-RevId: 602823670
Change-Id: I7a843cacca8201677c0f31249112c04f6c3e04cb

libwvdrmengine/oemcrypto/odk/test/odk_test_helper.h

@@ -28,7 +28,7 @@ enum ODK_FieldType {
   ODK_HASH,
   // The "stressable" types are the ones we can put in a stress test that packs
   // and unpacks random data and can expect to get back the same thing.
-  ODK_LAST_STRESSABLE_TYPE,
+  ODK_LAST_STRESSABLE_TYPE = ODK_HASH,
   // Put boolean after ODK_LAST_STRESSABLE_TYPE, so that we skip boolean type in
   // SerializeFieldsStress because we unpack any nonzero to 'true'.
   ODK_BOOL,