These are not used, as the nodes are constructed with a block allocator and always passed by pointer.
Reduces the Tint binary a bit:
7,759,776 -> 7,758,800
Makes some files have 100% code coverage which didn't before.
Bug: tint:1833
Change-Id: Iff4652deba92663677cc53e9506a829d0a4c12bf
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/124180
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>