chore: Remove trick to run tests in module only available with c-types feature

Author: jhg

Cargo.toml

@@ -24,12 +24,3 @@ log = "^0"
 
 [package.metadata.docs.rs]
 features = ["std", "c-types"]
-
-# TODO: find a better solution:
-# Work around for test with features like c-types to detect compile errors
-# like the one introduced with the commit 3a1d15f33e8e418ef6bee2b7b9e096780bd2c8ac
-# removing needed lifetime but tests and compilation without c-types did not fail,
-# see issue reply https://github.com/rust-lang/cargo/issues/2911#issuecomment-749580481
-# for more information
-[dev-dependencies]
-opaque-pointer = { path = ".", features = ["c-types"] }