Remove direct dependency on CRTU

Author: oxinabox

Project.toml

@@ -6,7 +6,6 @@ version = "0.6.17"
 AbstractFFTs = "621f4979-c628-5d54-868e-fcf4e3e8185c"
 ChainRules = "082447d4-558c-5d27-93f4-14fc19e9eca2"
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"
-ChainRulesTestUtils = "cdddcdb0-9152-4a09-a978-84456f9df70a"
 DiffRules = "b552c78f-8df3-52c6-915a-8e097449b14b"
 Distributed = "8ba89e20-285c-5b6f-9357-94700520ee1b"
 FillArrays = "1a297f60-69ca-5386-bcde-b61e274b549b"