We were only keeping track of `RawSyntax` node IDs to incrementally transfer a syntax tree via JSON. However, AFAICT the incremental JSON transfer option has been superceeded by `SyntaxParseActions`, which are more efficient.
So, let’s clean up and remove the `RawSyntax` node ID and JSON incremental transfer option.
In places that still need a notion of `RawSyntax` identity (like determining the reused syntax regions), use the `RawSyntax`’s pointer instead of the manually created ID.
In `incr_transfer_round_trip.py` always use the code path that uses the `SyntaxParseActions` and remove the transitional code that was still using the incremental JSON transfer but was never called.
Instead of having a heap-allocated RefCountedBox to store a SyntaxData's
parent, reference-count SyntaxData itself. This has a couple of
advantages:
- When passing SyntaxData around, only a pointer needs to be passed
instead of the entire struct contents. This is faster.
- We can later introduce a SyntaxDataRef, which behaves similar to
SyntaxData, but delegates the responsibility that the parent stays
alive to the user. While sacrificing guaranteed memory safety, this
means that SyntaxData can then be stack-allocated without any
ref-counting overhead.
If the position is in the region that is inserted by the edits,
'pre-edit' position shouldn't exist. So we cannot reuse the node at the
position.
rdar://problem/45259469
https://bugs.swift.org/browse/SR-8995
Also fix Edit::intersectsOrTouchesRange check only returning true when the
ranges overlapped, rather than when they overlapped or 'touched'.
Resolves rdar://problem/45108439
