(snap-backed-graphql-3) Add test for solid definition collisions
Added this toy pipeline to test solid def name collisions. When aliases
at diff layers in the stack with the same name point to different solid def.
The ensures dependency scoping is correct as you navigate up and down the solid
Test Plan: BK. View in dagit
Reviewers: alangenfeld, sashank, themissinghlink
Reviewed By: themissinghlink
Differential Revision: https://dagster.phacility.com/D2307