test more varinfos with parent contexts

[penelopeysm]

This bit in #984:

DynamicPPL.jl/src/test_utils/contexts.jl

Lines 83 to 94 in 3bb7ade

	@testset "initialisation and evaluation" begin
	new_model = contextualize(model, context)
	for vi in [DynamicPPL.VarInfo(), DynamicPPL.typed_varinfo(DynamicPPL.VarInfo())]
	# Initialisation
	_, vi = DynamicPPL.init!!(new_model, DynamicPPL.VarInfo())
	@test vi isa DynamicPPL.VarInfo
	# Evaluation
	_, vi = DynamicPPL.evaluate!!(new_model, vi)
	@test vi isa DynamicPPL.VarInfo
	end
	end
	end

only tests untyped and typed varinfo