Rename job to prevent conflict with job from build/maven.yml

New GC job uses compile-and-unit-test name, which overwrites job of the same name from build/maven.yml. The overwritten job executes at a later stage, and has conditions where it will not execute (for instance, merging to master branch).

This means when merging to master branch, compile-and-unit-test will not run, breaking the pipeline.

To resolve, I have renamed the job to gc-compile-and-unit-test. Please confirm whether this will suffice for gc, and whether my suspicion about currently broken pipelines is correct.

Thank you.