Do not pass source bytes to Loader.java at all and mark newlines for lazy DefNodes

[eregon]

Follow-up of #3983, implementing a variant of the first option, the difference being we create a new MarkNewlinesVisitor object vs keeping it around.
We also need to keep the Source object around to have access to line offsets, but that's fine as the first commit completely removes the need to pass the source byte[] to the Loader :)
With this, we can use lazy DefNode in TruffleRuby and be fully compatible with eager loading.

From the commits:

Do not pass source bytes to Loader.java at all

• That way we are sure it's not retained by it.
• Source#bytes seems to have no usages.
• Arrays.binarySearch() works just fine if the value is > the last array element.

Mark newlines for lazy DefNodes

• By running the MarkNewlinesVisitor on them when they are lazily loaded.
• See Make it possible to lazily deserialize DefNode in Loader.java #3983.
• Achieves the same nodes as with eager DefNode.

[eregon]

Benchmarks in truffleruby/truffleruby#4182 (comment), it's about 35% faster to parse the TruffleRuby core library!

[kddnewton]

Seems fine to me. @enebo?

[eregon]

This is basically fixing #3983 to make it usable, merging to unblock truffleruby/truffleruby#4182 and a chain of PRs on top of it.

If anyone wants to access the sourceBytes they can easily keep it themselves as they are given to Parser.parseAndSerialize(sourceBytes, parsingOptions).