test: fix initializesystem tests

Problems initialize to the same values, retcode changes

Author: AayushSabharwal

test/initializationsystem.jl

@@ -229,13 +229,13 @@ allinit = unknowns(sys) .=> initsol[unknowns(sys)]
 prob = ODEProblem(sys, allinit, (0, 0.1))
 sol = solve(prob, Rodas5P(), initializealg = BrownFullBasicInit())
 # If initialized incorrectly, then it would be InitialFailure
-@test sol.retcode == SciMLBase.ReturnCode.Unstable
+@test sol.retcode == SciMLBase.ReturnCode.MaxIters
 @test maximum(abs.(initsol[conditions][1])) < 1e-14
 
 prob = ODEProblem(sys, [], (0, 0.1), check = false)
 sol = solve(prob, Rodas5P())
 # If initialized incorrectly, then it would be InitialFailure
-@test sol.retcode == SciMLBase.ReturnCode.Unstable
+@test sol.retcode == SciMLBase.ReturnCode.MaxIters
 @test maximum(abs.(initsol[conditions][1])) < 1e-14
 
 @connector Flange begin