Consolidate and create known effects before creating skia context.

This is a mechanical refactor.
This is required so that graphite can know the user defined effects before precompilation.
Specifying the user defined effects to graphite will be done in another CL.

Bug: 380159947
Test: Test different shaders in the OS with ganesh and graphite. Everything seems to work as expected.
Flag: EXEMPT refactor
Change-Id: I6ef63e360f42a563dc7ef8822fc5585b7dfa8ad1