This greatly simplifies the semantics around the const buffers.
When they can no longer be made writable, there is no longer any need for "deconstification".
I decided to call the method "makeReadOnly" to distinguish it from "asReadOnly" that is seen in ByteBuf and ByteBuffer. The latter two return read-only _views_ of the buffer, while makeReadOnly changes the state of the buffer in-place.
Then run those tests in independent surefire forks.
This should allow Maven to hold on to less test metadata, and cope better with the large number of tests.
