Remove Printf dependency from tests

Replace Printf.@printf with standard println() function. The Printf module
was only used in one test file for conditional debug printing, which can
be accomplished with the built-in println function.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: ChrisRackauckas

Project.toml

@@ -258,7 +258,6 @@ ODEProblemLibrary = "fdc4e326-1af4-4b90-96e7-779fcce2daa5"
 ParameterizedFunctions = "65888b18-ceab-5e60-b2b9-181511a3b968"
 Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
 PoissonRandom = "e409e4f3-bfea-5376-8464-e040bb5c01ab"
-Printf = "de0858da-6303-5e67-8744-51eddeeeb8d7"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 RecursiveFactorization = "f2c3362d-daeb-58d1-803e-2bc74f2840b4"
 ReverseDiff = "37e2e3b7-166d-5795-8a7a-e32c996b4267"
@@ -273,4 +272,4 @@ Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 Unitful = "1986cc42-f94f-5a68-af5c-568840ba703d"
 
 [targets]
-test = ["Calculus", "ComponentArrays", "Symbolics", "AlgebraicMultigrid", "IncompleteLU", "DiffEqCallbacks", "DifferentiationInterface", "DiffEqDevTools", "ODEProblemLibrary", "ElasticArrays", "ExplicitImports", "InteractiveUtils", "ParameterizedFunctions", "JLArrays", "PoissonRandom", "Printf", "Random", "ReverseDiff", "SafeTestsets", "SparseArrays", "Statistics", "StructArrays", "Test", "Unitful", "ModelingToolkit", "Pkg", "NLsolve", "RecursiveFactorization", "SparseConnectivityTracer", "SparseMatrixColorings"]
+test = ["Calculus", "ComponentArrays", "Symbolics", "AlgebraicMultigrid", "IncompleteLU", "DiffEqCallbacks", "DifferentiationInterface", "DiffEqDevTools", "ODEProblemLibrary", "ElasticArrays", "ExplicitImports", "InteractiveUtils", "ParameterizedFunctions", "JLArrays", "PoissonRandom", "Random", "ReverseDiff", "SafeTestsets", "SparseArrays", "Statistics", "StructArrays", "Test", "Unitful", "ModelingToolkit", "Pkg", "NLsolve", "RecursiveFactorization", "SparseConnectivityTracer", "SparseMatrixColorings"]

test/regression/ode_dense_tests.jl

@@ -1,14 +1,14 @@
 using OrdinaryDiffEq, Test, DiffEqBase
 using OrdinaryDiffEqCore
-using ForwardDiff, Printf
+using ForwardDiff
 import ODEProblemLibrary: prob_ode_linear,
                           prob_ode_2Dlinear,
                           prob_ode_bigfloatlinear, prob_ode_bigfloat2Dlinear
 # use `PRINT_TESTS = true` to print the tests, including results
 const PRINT_TESTS = false
 print_results(x) =
     if PRINT_TESTS
-        @printf("%s \n", x)
+        println(x)
     end
 
 # points and storage arrays used in the interpolation tests