Motivation: CoreUObject, taskgraph and threads are global constructs and need to be initialized as such and are expensive to setup/teardown before/after multiple single tests.
Introduced --global-setup and --no-global-setup to control execution of global test setup.
Unit tests that rely heavily on mocking and are designed to run without any global context should use --no-global-setup
Other: Removed CoreTestFixture and applied minor fixes wherever things didn't make sense.
One particular CoreUObject test was converted but had always failed to run on non-desktop platforms. It needs to be addressed ASAP.
#preflight 625873c7e304a95465fc148e
#rb Devin.Doucette, Zousar.Shaker
[CL 19769262 by chris constantinescu in ue5-main branch]
