message: Add README about spectest
diff: @@ -20,6 +20,10 @@ IV) First class support for determistic applications (*blockchain*)
  - Support the bigint API
  - Support runtime metering in the interpreter
  +## Testing
  +
  +To read about testing see [fizzy-spectests](./test/spectests/README.md).
  +
  ## License
  Apache 2.0
  