* Moved global variable resolving logic to new function Resolver::GlobalVariable, and moved validation logic there.
* Moved global variable-related tests to resolver tests.
* Fixed many tests that started failing after this change, mainly because many globals were declared with no storage class. I set most of these to "Input".
Bug: tint:642
Change-Id: I0f8ea2091ed2bb3faa358f9497cd884b2994a40f
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/46940
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>