Re-enable commented out Shooting type stability tests

[ChrisRackauckas-Claude]

The Shooting and MultipleShooting @inferred tests in test/misc/type_stability_tests.jl are currently commented out because they fail due to deep type instability originating from NonlinearSolve/OrdinaryDiffEq.

The commented out tests are in both the "Multi-Point BVP" and "Two-Point BVP" sections:

# @testset "Shooting Methods" begin
#     @inferred solve(mpbvp_iip, Shooting(Tsit5(); jac_alg))
#     @inferred solve(mpbvp_oop, Shooting(Tsit5(); jac_alg))
#     @inferred solve(mpbvp_iip, MultipleShooting(5, Tsit5(); jac_alg))
#     @inferred solve(mpbvp_oop, MultipleShooting(5, Tsit5(); jac_alg))
# end

These were previously using @testset ... skip = true which is not supported on Julia 1.10/1.11 (see #429). They were commented out as a workaround.

Once the upstream type instability in NonlinearSolve/OrdinaryDiffEq is resolved, these tests should be uncommented.